Proxima Centauri, or Alpha Centauri C, is a red dwarf, a small low-mass star, about 4.244 light-years from the Sun in the constellation of Centaurus. It is the nearest-known star to the Sun. With a quiescent apparent magnitude of 11.13, it is too faint to be seen with the naked eye. Proxima Centauri forms a third component of the Alpha Centauri system with a separation of about 12,950 AU and an orbital period of 550,000 years. At present Proxima is 2.18° to the southwest of Alpha Centauri. Because of Proxima Centauri's proximity to Earth, its angular diameter can be measured directly; the star is about one-seventh the diameter of the Sun. It has a mass about an eighth of the Sun's mass, its average density is about 33 times that of the Sun. Although it has a low average luminosity, Proxima is a flare star that undergoes random dramatic increases in brightness because of magnetic activity; the star's magnetic field is created by convection throughout the stellar body, the resulting flare activity generates a total X-ray emission similar to that produced by the Sun.
The mixing of the fuel at Proxima Centauri's core through convection and its low energy-production rate mean that it will be a main-sequence star for another four trillion years, or nearly 300 times the current age of the universe. In 2016, the European Southern Observatory announced the discovery of Proxima Centauri b, a planet orbiting the star at a distance of 0.05 AU with an orbital period of 11.2 Earth days. Its estimated mass is at least 1.3 times that of the Earth. The equilibrium temperature of Proxima b is estimated to be within the range of where water could exist as liquid on its surface, thus placing it within the habitable zone of Proxima Centauri, although because Proxima Centauri is a red dwarf and a flare star, whether it could support life is disputed. Previous searches for orbiting companions had ruled out the presence of brown dwarfs and supermassive planets. In 1915, the Scottish astronomer Robert Innes, Director of the Union Observatory in Johannesburg, South Africa, discovered a star that had the same proper motion as Alpha Centauri.
He suggested. In 1917, at the Royal Observatory at the Cape of Good Hope, the Dutch astronomer Joan Voûte measured the star's trigonometric parallax at 0.755″±0.028″ and determined that Proxima Centauri was the same distance from the Sun as Alpha Centauri. It was found to be the lowest-luminosity star known at the time. An accurate parallax determination of Proxima Centauri was made by American astronomer Harold L. Alden in 1928, who confirmed Innes's view that it is closer, with a parallax of 0.783″±0.005″. In 1951, American astronomer Harlow Shapley announced. Examination of past photographic records showed that the star displayed a measurable increase in magnitude on about 8% of the images, making it the most active flare star known; the proximity of the star allows for detailed observation of its flare activity. In 1980, the Einstein Observatory produced a detailed X-ray energy curve of a stellar flare on Proxima Centauri. Further observations of flare activity were made with the EXOSAT and ROSAT satellites, the X-ray emissions of smaller, solar-like flares were observed by the Japanese ASCA satellite in 1995.
Proxima Centauri has since been the subject of study by most X-ray observatories, including XMM-Newton and Chandra. In 2016, the International Astronomical Union organized a Working Group on Star Names to catalogue and standardize proper names for stars; the WGSN approved the name Proxima Centauri for this star on August 21, 2016 and it is now so included in the List of IAU approved Star Names. Because of Proxima Centauri's southern declination, it can only be viewed south of latitude 27° N. Red dwarfs such as Proxima Centauri are far too faint to be seen with the naked eye. From Alpha Centauri A or B, Proxima would only be seen as a fifth magnitude star, it has an apparent visual magnitude of 11, so a telescope with an aperture of at least 8 cm is needed to observe it under ideal viewing conditions—under clear, dark skies with Proxima Centauri well above the horizon. In 2018, a superflare was observed from Proxima Centauri, the strongest flare seen; the optical brightness increased by a factor of 68 to magnitude 6.8.
It is estimated that similar flares occur around five times every year but are of such short duration, just a few minutes, that they have never been observed before. Proxima Centauri is a red dwarf, because it belongs to the main sequence on the Hertzsprung–Russell diagram and is of spectral class M5.5. M5.5 means. Its absolute visual magnitude, or its visual magnitude as viewed from a distance of 10 parsecs, is 15.5. Its total luminosity over all wavelengths is 0.17% that of the Sun, although when observed in the wavelengths of visible light the eye is most sensitive to, it is only 0.0056% as luminous as the Sun. More than 85% of its radiated power is at infrared wavelengths, it has a regular activity cycle of starspots. In 2002, optical interferometry with the Very Large Telescope found that the angular diameter of Proxima Centauri was 1.02±0.08 mas. Because its distance is known, the actual diameter of Proxima Centauri can be calculated to be about 1/7 that of the Sun, or 1.5 times that of Jupiter.
The star's mass, estimated from stellar theory, is 129 Jupiter masses. The mass has been calculated directly, although with less precision, from observations of microlensing events to be 0.150+0.062−
Christopher Columbus was an Italian explorer and colonist who completed four voyages across the Atlantic Ocean under the auspices of the Catholic Monarchs of Spain. He led the first European expeditions to the Caribbean, Central America, South America, initiating the permanent European colonization of the Americas. Columbus discovered the viable sailing route to the Americas, a continent, not known to the Old World. While what he thought he had discovered was a route to the Far East, he is credited with the opening of the Americas for conquest and settlement by Europeans. Columbus's early life is somewhat obscure, but scholars agree that he was born in the Republic of Genoa and spoke a dialect of Ligurian as his first language, he went to sea at a young age and travelled as far north as the British Isles and as far south as what is now Ghana. He married Portuguese noblewoman Filipa Moniz Perestrelo and was based in Lisbon for several years, but took a Spanish mistress. Though self-educated, Columbus was read in geography and history.
He formulated a plan to seek a western sea passage to the East Indies, hoping to profit from the lucrative spice trade. After years of lobbying, the Catholic Monarchs of Spain agreed to sponsor a journey west, in the name of the Crown of Castile. Columbus left Spain in August 1492 with three ships, after a stopover in the Canary Islands made landfall in the Americas on 12 October, his landing place was an island in the Bahamas, known by its native inhabitants as Guanahani. Columbus subsequently visited Cuba and Hispaniola, establishing a colony in what is now Haiti—the first European settlement in the Americas since the Norse colonies 500 years earlier, he arrived back in Spain in early 1493. Word of his discoveries soon spread throughout Europe. Columbus would make three further voyages to the New World, exploring the Lesser Antilles in 1493, Trinidad and the northern coast of South America in 1498, the eastern coast of Central America in 1502. Many of the names he gave to geographical features—particularly islands—are still in use.
He continued to seek a passage to the East Indies, the extent to which he was aware that the Americas were a wholly separate landmass is uncertain. Columbus's strained relationship with the Spanish crown and its appointed colonial administrators in America led to his arrest and removal from Hispaniola in 1500, to protracted litigation over the benefits that he and his heirs claimed were owed to them by the crown. Columbus's expeditions inaugurated a period of exploration and colonization that lasted for centuries, helping create the modern Western world; the transfers between the Old World and New World that followed his first voyage are known as the Columbian exchange, the period of human habitation in the Americas prior to his arrival is known as the Pre-Columbian era. Columbus's legacy continues to be debated, he was venerated in the centuries after his death, but public perceptions have changed as recent scholars have given attention to negative aspects of his life, such as his role in the extinction of the Taíno people, his promotion of slavery, allegations of tyranny towards Spanish colonists.
Many landmarks and institutions in the Western Hemisphere bear his name, including the country of Colombia. The name Christopher Columbus is the Anglicisation of the Latin Christophorus Columbus, his name in Ligurian is Cristoffa Corombo, in Italian Cristoforo Colombo, in Spanish is Cristóbal Colón, in Portuguese is Cristóvão Colombo. He was born before 31 October 1451 in the territory of the Republic of Genoa, though the exact location remains disputed, his father was Domenico Colombo, a middle-class wool weaver who worked both in Genoa and Savona and who owned a cheese stand at which young Christopher worked as a helper. His mother was Susanna Fontanarossa. Bartolomeo, Giovanni Pellegrino, Giacomo were his brothers. Bartolomeo worked in a cartography workshop in Lisbon for at least part of his adulthood, he had a sister named Bianchinetta. Columbus never wrote in his native language, presumed to have been a Genoese variety of Ligurian: his name in the 16th-century Genoese language would have been Cristoffa Corombo.
In one of his writings, he says he went to sea at the age of 10. In 1470, the Columbus family moved to Savona. In the same year, Christopher was on a Genoese ship hired in the service of René of Anjou to support his attempt to conquer the Kingdom of Naples; some modern historians have argued that he was not from Genoa but, from the Aragon region of Spain or from Portugal. These competing hypotheses have been discounted by mainstream scholars. In 1473, Columbus began his apprenticeship as business agent for the important Centurione, Di Negro and Spinola families of Genoa, he made a trip to Chios, an Aegean island ruled by Genoa. In May 1476, he took part in an armed convoy sent by Genoa to carry valuable cargo to northern Europe, he docked in Bristol and Galway, Ireland. In 1477, he was in Iceland. In the autumn of 1477, he sailed on a Portuguese ship from Galway to Lisbon, where he found his brother Bartolomeo, they continued trading for the Centurione family. Columbus based himself in Lisbon from 1477 to 1485.
He married Filipa Moniz Perestrelo, daughter of the Porto Santo governor and Portuguese nobleman of
Robert A. Heinlein
Robert Anson Heinlein was an American science-fiction author, aeronautical engineer, retired Naval officer. Called the "dean of science fiction writers", He was among the first to emphasize scientific accuracy in his fiction, was thus a pioneer of the subgenre of hard science fiction, his work continues to have an influence on the science-fiction genre, on modern culture more generally. Heinlein became one of the first American science-fiction writers to break into mainstream magazines such as The Saturday Evening Post in the late 1940s, he was one of the best-selling science-fiction novelists for many decades, he, Isaac Asimov, Arthur C. Clarke are considered the "Big Three" of English-language science fiction authors. Notable Heinlein works include Stranger in a Strange Land, Starship Troopers and The Moon Is a Harsh Mistress, his work sometimes had controversial aspects, such as plural marriage in The Moon is a Harsh Mistress, militarism in Starship Troopers and technologically competent women characters that were strong and independent, yet stereotypically feminine – such as Friday.
A writer of numerous science-fiction short stories, Heinlein was one of a group of writers who came to prominence under the editorship of John W. Campbell at Astounding Science Fiction magazine, though Heinlein denied that Campbell influenced his writing to any great degree. Within the framework of his science-fiction stories, Heinlein addressed certain social themes: the importance of individual liberty and self-reliance, the obligation individuals owe to their societies, the influence of organized religion on culture and government, the tendency of society to repress nonconformist thought, he speculated on the influence of space travel on human cultural practices. Heinlein was named the first Science Fiction Writers Grand Master in 1974. Four of his novels won Hugo Awards. In addition, fifty years after publication, seven of his works were awarded "Retro Hugos"—awards given retrospectively for works that were published before the Hugo Awards came into existence. In his fiction, Heinlein coined terms that have become part of the English language, including "grok", "waldo", "speculative fiction", as well as popularizing existing terms like "TANSTAAFL", "pay it forward", "space marine".
He anticipated mechanical computer-aided design with "Drafting Dan" and described a modern version of a waterbed in his novel Beyond This Horizon, though he never patented nor built one. In the first chapter of the novel Space Cadet he anticipated the cell-phone, 35 years before Motorola invented the technology. Several of Heinlein's works have been adapted for television. Heinlein was born on July 7, 1907 in Butler, Missouri, he was a 6th-generation German-American: a family tradition had it that Heinleins fought in every American war starting with the War of Independence. His childhood was spent in Missouri; the outlook and values of this time and place had a definite influence on his fiction his works, as he drew upon his childhood in establishing the setting and cultural atmosphere in works like Time Enough for Love and To Sail Beyond the Sunset. Heinlein's experience in the U. S. Navy exerted a strong influence on his writing, he graduated from the U. S. Naval Academy in Annapolis, with the class of 1929.
Shortly after graduation, he was commissioned as an ensign by the U. S. Navy, he advanced to lieutenant, junior grade while serving aboard the new aircraft carrier USS Lexington in 1931, where he worked in radio communications in its earlier phases, with the carrier's aircraft. The captain of this carrier was Ernest J. King, who served as the Chief of Naval Operations and Commander-in-Chief, U. S. Fleet during World War II. Heinlein was interviewed during his years by military historians who asked him about Captain King and his service as the commander of the U. S. Navy's first modern aircraft carrier. Heinlein served as gunnery officer aboard the destroyer USS Roper in 1933 and 1934, reaching the rank of lieutenant, his brother, Lawrence Heinlein, served in the U. S. Army, the U. S. Air Force, the Missouri National Guard, reaching the rank of major general in the National Guard. In 1929, Heinlein married Elinor Curry of Kansas City. However, their marriage only lasted about a year, his second marriage in 1932 to Leslyn MacDonald lasted for 15 years.
MacDonald was, according to the testimony of Heinlein's Navy friend, Rear Admiral Cal Laning, "astonishingly intelligent read, liberal, though a registered Republican," while Isaac Asimov recalled that Heinlein was, at the time, "a flaming liberal". At the Philadelphia Naval Shipyard Heinlein met and befriended a chemical engineer named Virginia "Ginny" Gerstenfeld. After the war, her engagement having fallen through, she moved to UCLA for doctoral studies in chemistry and made contact again; as his second wife's alcoholism spun out of control, Heinlein moved out and the couple filed for divorce. Heinlein's friendship with Virginia turned into a relationship and on October 21, 1948 — shortly after the decree nisi came through — they married in the town of Raton, New Mexico, shortly after setting up housekeeping in Colorado, they remained married until Heinlein's death. As Heinlein's increasing success as a writer resolved their initial financial woes, they had a house custom built with various innovative features described in an article in Popular Mechanics.
In 1965, after various chronic health problems of
Future History (Heinlein)
The Future History, by Robert A. Heinlein, describes a projected future of the human race from the middle of the 20th century through the early 23rd century; the term Future History was coined by John W. Campbell, Jr. in the February 1941 issue of Astounding Science Fiction. Campbell published an early draft of Heinlein's chart of the series in the March 1941 issue. Heinlein wrote most of the Future History stories early in his career, between 1939 and 1941 and between 1945 and 1950. Most of the Future History stories written prior to 1967 are collected in The Past Through Tomorrow, which contains the final version of the chart; that collection does not include Common Sense. Groff Conklin called Future History "the greatest of all histories of tomorrow", it was nominated for the Hugo Award for Best All-Time Series in 1966, along with the Barsoom series by Edgar Rice Burroughs, the Lensman series by E. E. Smith, the Foundation series by Isaac Asimov, The Lord of the Rings series by J. R. R. Tolkien, but lost to Asimov's Foundation series.
For the most part, The Past Through Tomorrow defines a core group of stories that are within the Future History series. However, Heinlein scholars agree that some stories not included in the anthology belong to the Future History series, that some that are included are only weakly linked to it. James Gifford adds Time Enough for Love, published after The Past Through Tomorrow, "Let There Be Light", not included in The Past Through Tomorrow because the collection editor disliked it or because Heinlein himself considered it to be inferior. However, he considers Time Enough for Love to be a borderline case, he considers The Number of the Beast, The Cat Who Walks Through Walls, To Sail Beyond the Sunset to be too weakly linked to the Future History to be included. Bill Patterson includes To Sail Beyond the Sunset, on the theory that the discrepancies between it and the rest of the Future History are explained by assigning it to the same "bundle of related timelines" in the World as Myth multiverse.
However, he lists a number of stories that he believes were never intended to be part of Future History though they were included in The Past Through Tomorrow: "Life-Line", "The Menace from Earth", "—We Also Walk Dogs", the stories published in the Saturday Evening Post. He agrees with Gifford; the story "—And He Built a Crooked House—" was included only in the pre-war chart and never since. The Heinlein juveniles do not hew to the Future History outline. Gifford states that "Although the twelve juvenile novels are not inconsistent with the Future History, neither do they form a thorough match with that series for adult readers, it is not recognized that they are a reasonably consistent'Future History' of their own... At least one major story specified in the Future History chart, the revolution on Venus, ended up being told in the framework of the juveniles as Between Planets." The novel Variable Star, written by Spider Robinson from Heinlein's detailed outline, incorporates some elements of both the Future History and the universe of the Heinlein juveniles.
The adult short story "The Long Watch", included in Future History story collections, connects to Space Cadet through the character of Ezra Dahlquist, the central character of the first, memorialized in the second. The following is a chronology of the Future History. Years are included to indicate. Stories that were planned but never written are noted. "Life-Line" "Let There Be Light" Word Edgewise"The Roads Must Roll" "Blowups Happen" "The Man Who Sold the Moon" "Delilah and the Space Rigger" "Space Jockey" "Requiem" "The Long Watch" "Gentlemen, Be Seated!" "The Black Pits of Luna" "It's Great to Be Back!" "—We Also Walk Dogs" "Searchlight" "Ordeal in Space" "The Green Hills of Earth"Fire Down Below"Logic of Empire" "The Menace from Earth"The Sound of His Wings Eclipse The Stone Pillow"If This Goes On—" "Coventry" "Misfit" "Universe" Methuselah's Children "Universe" Time Enough for Love To Sail Beyond the Sunset The chart published in the collection Revolt in 2100 includes several unwritten stories, which Heinlein describes in a postscript.
"Fire Down Below," about a revolution in Antarctica, would have been set in the early 21st century. Three more unwritten stories fill in the history from just before "Logic of Empire" in the early 21st century through the beginning of "If This Goes On—". "The Sound of His Wings" covers Nehemiah Scudder's early life as a television evangelist through his rise to power as the First Prophet. "Eclipse" describes independence movements on Venus. "The Stone Pillow" details the rise of the resistance movement from the early days of the theocracy through the beginning of "If This Goes On—". These stories were key points in the Future History, so Heinlein gave a rough description of Nehemiah Scudder
Startling Stories was an American pulp science fiction magazine, published from 1939 to 1955 by publisher Ned Pines' Standard Magazines. It was edited by Mort Weisinger, the editor of Thrilling Wonder Stories, Standard's other science fiction title. Startling ran a lead novel in every issue; when Standard Magazines acquired Thrilling Wonder in 1936, it gained the rights to stories published in that magazine's predecessor, Wonder Stories, selections from this early material were reprinted in Startling as "Hall of Fame" stories. Under Weisinger the magazine focused on younger readers and, when Weisinger was replaced by Oscar J. Friend in 1941, the magazine became more juvenile in focus, with clichéd cover art and letters answered by a "Sergeant Saturn". Friend was replaced by Sam Merwin, Jr. in 1945, Merwin was able to improve the quality of the fiction publishing Arthur C. Clarke's Against the Fall of Night, several other well-received stories. Much of Startling's cover art was painted by Earle K. Bergey, who became associated with the magazine, painting every cover between 1940 and 1952.
He was known for equipping his heroines with brass bras and implausible costumes, the public image of science fiction in his day was created by his work for Startling and other magazines. Merwin left in 1951, Samuel Mines took over. In mid-1952, Standard attempted to change Startling's image by adopting a more sober title typeface and reducing the sensationalism of the covers, but by 1955 the pulp magazine market was collapsing. Startling absorbed its two companion magazines, Thrilling Wonder and Fantastic Story Magazine, in early 1955, but by the end of that year it too ceased publication. Ron Hanna of Wild Cat Books revived Startling Stories in 2007. Wild Cat Books folded in 2013. A statement of the closure is still posted on the Facebook page All Pulp dated March 12, 2013. Although science fiction had been published before the 1920s, it did not begin to coalesce into a separately marketed genre until the appearance in 1926 of Amazing Stories, a pulp magazine published by Hugo Gernsback. By the end of the 1930s the field was booming.
Standard Magazines, a pulp publishing company owned by Ned Pines, acquired its first science fiction magazine, Thrilling Wonder Stories, from Gernsback in 1936. Mort Weisinger, the editor of Thrilling Wonder, printed an editorial in February 1938 asking readers for suggestions for a companion magazine. Response was positive, the new magazine, titled Startling Stories, was duly launched, with a first issue, dated January 1939. Initial pay rates were half a cent per word, lower than the leading magazines of the day. Startling was launched on a bimonthly schedule, alternating months with Thrilling Wonder Stories, though in 1940 Thrilling moved to a monthly schedule that lasted for over a year; the first editor was Mort Weisinger, an active fan in the early 1930s and had joined Standard Magazines in 1935, editing Thrilling Wonder from 1936. Weisinger left in 1941 to take a new post as editor of Superman, was replaced by Oscar J. Friend, an established writer of pulp fiction, though his experience was in western fiction rather than sf.
During Friend's tenure Startling slipped from bimonthly to quarterly publication. Friend lasted for a little over two years, was replaced by Sam Merwin, Jr. as of the Winter 1945 issue. Merwin succeeded in making Startling popular and successful, the bimonthly schedule was resumed in 1947. At the start of 1952 Startling switched to a monthly schedule. Merwin left shortly before this switch, he was replaced by Samuel Mines, who had worked with Standard's Western magazines, though he was a science fiction aficionado. Street & Smith, one of the longest established and most respected publishers, shut down all of their pulp magazines in the summer of 1949; the pulps were dying as a result of the success of paperbacks. Standard continued with Startling and Thrilling. In 1954, Fredric Wertham published Seduction of the Innocent, a book in which he asserted that comics were inciting children to violence. A subsequent Senate subcommittee hearing led to a backlash against comics, the publishers dropped titles in response.
The financial impact spread to pulp magazines, since a publisher would publish both. A 1955 strike by American News Corporation, the main distributor in the U. S. meant that magazines never made it to the newsstands. Startling was one of the casualties; the schedule had returned from monthly to bimonthly in 1953, it became a quarterly in early 1954. Thrilling Wonder published its last issue in early 1955, was merged with Startling, as was Fantastic Story Magazine, another companion publication, but the combined magazine lasted only three more issues. Mines left the magazine at the end of 1954; the final issue was dated Fall 1955. From the beginning, every issue of Startling contained a complete novel, along with one or two short stories.
Voyages of Christopher Columbus
In 1492, a Spanish-based transatlantic maritime expedition led by Italian explorer Christopher Columbus encountered the Americas, continents which were unknown in Europe and were outside the Old World political and economic system. The four voyages of Columbus began the Spanish colonization of the Americas. For a long time it was believed that Columbus and his crew had been the first Europeans to make landfall in the Americas. In fact they were not the first explorers from Europe to reach the Americas, having been preceded by the Viking expedition led by Leif Erikson in the 11th century. Columbus was an Italian-born navigator sailing for the Crown of Castile in search of a westward route to Asia, to access the sources of spices and other oriental goods; this failed when he encountered the New World between Asia. Columbus made a total of four voyages to the Americas between 1492 and 1502, setting the stage for the European exploration and colonization of the Americas leading to the Columbian Exchange.
At the time of the Columbus voyages, the Americas were inhabited by the Indigenous Americans, the descendants of Paleo-Indians who crossed Beringia from Asia to North America beginning around 20,000 years ago. Columbus's voyages led to the widespread knowledge that a continent existed west of Europe and east of Asia; this breakthrough in geographical science led to the exploration and colonization of the New World by Spain and other European sea powers, is sometimes cited as the start of the modern era. Spain and other European kingdoms sent expeditions and established colonies throughout the New World, converted the native inhabitants to Christianity, built large trade networks across the Atlantic, which introduced new plants and food crops to both continents; the search for a westward route to Asia continued in 1513 when Vasco Nuñez de Balboa crossed the narrow Isthmus of Panama to become the first European to sight the Pacific Ocean. The search was completed in 1521, when the Castilian Magellan expedition sailed across the Pacific and reached Southeast Asia.
Portugal had been the main European power interested in pursuing trade routes overseas. Their next-door neighbors, Castile had been somewhat slower to begin exploring the Atlantic because of the bigger land area it had to re-conquer from the Moors, it was not until the late 15th century, following the dynastic union of the Crowns of Castile and Aragon and the completion of the Reconquista, that the unified crowns of what would become Spain emerged and became committed to looking for new trade routes and colonies overseas. In 1492 the joint rulers conquered the Moorish kingdom of Granada, providing Castile with African goods through tribute. Columbus had failed to convince King John II of Portugal to fund his exploration of a western route, but the new king and queen of the re-conquered Spain decided to fund Columbus's expedition in hopes of bypassing Portugal's lock on Africa and the Indian Ocean, reaching Asia by traveling west, he proposed the king equip three sturdy ships and grant Columbus one year's time to sail out west into the Atlantic, search for a western route to India, return.
Columbus requested he be made "Great Admiral of the Ocean Sea", appointed governor of any and all lands he discovered, be given one-tenth of all revenue from those lands. The king submitted the proposal to his experts, it was their considered opinion that Columbus's estimation of a travel distance of 2,400 miles was, in fact, far too short. In 1488 Columbus appealed to the court of Portugal, receiving a new invitation for an audience with King John II; this proved unsuccessful, in part because not long afterwards Bartolomeu Dias returned to Portugal following a successful rounding of the southern tip of Africa. With an eastern sea route now under its control, Portugal was no longer interested in trailblazing a western trade route to Asia crossing unknown seas. Columbus traveled from Portugal to Castile to convince the Catholic Monarchs of Castile and Aragon to finance the expedition. King Ferdinand II of Aragon married Queen Isabella I of Castile in 1469, uniting the two largest kingdoms into what would be the Spanish Crown.
They were known jointly as the Catholic Monarchs, ruled their kingdoms independently, but had common internal and foreign policies. Columbus was granted an audience with them, they pronounced the idea impractical, advised the monarchs not to support the proposed venture. However, to expand the Spanish empire and Catholicism in the name of Spanish Kings, to assure a better market position in trading, the Queen gave Columbus an annual allowance of 12,000 maravedis and part of the newly conquered lands. After continually lobbying at the royal court and enduring two years of negotiations, Columbus succeeded in January 1492. Queen Isabella's forces had just conquered the Moorish Emirate of Granada, the last Muslim stronghold of Al-Andalus on the Iberian peninsula, for Castile. Isabella and Ferdinand received Columbus in the Alcázar in Córdoba to support his plans; the monarchs left it to the royal treasurer to shift funds among various royal accounts on behalf of the enterprise. Columbus was to be would receive a portion of all profits.
The terms were unusually generous but, as his son