Leiden is a city and municipality in the province of South Holland, Netherlands. The municipality of Leiden had a population of 123,856 in August 2017, but the city forms one densely connected agglomeration with its suburbs Oegstgeest, Leiderdorp and Zoeterwoude with 206,647 inhabitants; the Netherlands Central Bureau of Statistics further includes Katwijk in the agglomeration which makes the total population of the Leiden urban agglomeration 270,879, in the larger Leiden urban area Teylingen and Noordwijkerhout are included with in total 348,868 inhabitants. Leiden is located on the Oude Rijn, at a distance of some 20 kilometres from The Hague to its south and some 40 km from Amsterdam to its north; the recreational area of the Kaag Lakes lies just to the northeast of Leiden. A university city since 1575, Leiden has been one of Europe's most prominent scientific centres for more than four centuries. Leiden is a typical university city, university buildings are scattered throughout the city and the many students from all over the world give the city a bustling and international atmosphere.

Many important scientific discoveries have been made here, giving rise to Leiden's motto: ‘City of Discoveries’. The city houses Leiden University, the oldest university of the Netherlands, Leiden University Medical Center. Leiden University is one of Europe's top universities, with thirteen Nobel Prize winners, it is a member of the League of European Research Universities and positioned in all international academic rankings. It is twinned with the location of the United Kingdom's oldest university. Leiden University and Leiden University of Applied Sciences together have around 35,000 students. Modern scientific medical research and teaching started in the early 18th century in Leiden with Boerhaave. Leiden is a city with a rich cultural heritage, not only in science, but in the arts. One of the world's most famous painters, was born and educated in Leiden. Other famous Leiden painters include Jan van Goyen and Jan Steen. Leiden was formed on an artificial hill at the confluence of the rivers Nieuwe Rijn.

In the oldest reference to this, from circa 860, the settlement was called Leithon. The name is said to be from Germanic *leitha- "canal" in dative pluralis, thus meaning "at the canals". "Canal" is not the proper word. A leitha was a human-modified natural river natural artificial. Leiden has in the past erroneously been associated with the Roman outpost Lugdunum Batavorum; this particular castellum was thought to be located at the Burcht of Leiden, the city's name was thought to be derived from the Latin name Lugdunum. However the castellum was in fact closer to the town of Katwijk, whereas the Roman settlement near modern-day Leiden was called Matilo; the landlord of Leiden, situated in a stronghold on the hill, was subject to the Bishop of Utrecht but around 1100 the burgraves became subject to the county of Holland. This county got its name in 1101 from a domain near the stronghold: Holland. Leiden was sacked in 1047 by Emperor Henry III. Early 13th century, Countess of Holland took refuge here when she was fighting in a civil war against her uncle, William I, Count of Holland.

He captured Ada. Leiden received city rights in 1266. In 1389, its population had grown to about 4,000 persons. In 1420, during the Hook and Cod wars, Duke John III of Bavaria along with his army marched from Gouda in the direction of Leiden in order to conquer the city since Leiden did not pay the new Count of Holland Jacqueline, Countess of Hainaut, his niece and only daughter of Count William VI of Holland. Burgrave Filips of Wassenaar and the other local noblemen of the Hook faction assumed that the duke would besiege Leiden first and send small units out to conquer the surrounding citadels, but John of Bavaria chose to attack the citadels first. He rolled the cannons along with his army but one, too heavy went by ship. By firing at the walls and gates with iron balls the citadels fell one by one. Within a week John of Bavaria conquered the castles of Poelgeest, Ter Does, Hoichmade, de Zijl, ter Waerd, Warmond and de Paddenpoel. On 24 June the army appeared before the walls of Leiden. On 17 August 1420, after a two-month siege the city surrendered to John of Bavaria.

The burgrave Filips of Wassenaar was stripped of his offices and rights and lived out his last years in captivity. Leiden flourished in the 17th century. At the close of the 15th century the weaving establishments of Leiden were important, after the expulsion of the Spaniards Leiden cloth, Leiden baize and Leiden camlet were familiar terms. In the same period, Leiden developed an important publishing industry; the influential printer Christoffel Plantijn lived there at one time. One of his pupils was Lodewijk Elzevir, who established the largest bookshop and printing works in Leiden, a business continued by his descendants through 1712 and the name subsequently adopted by contemporary publisher Elsevier. In 1572, the city sided with the Dutch revolt against Spanish rule and played an important role in the Eighty Years' War. Besieged from May until October 1574 by the Spanish, Leiden was relieved by the cutting of the dikes, thus enabling ships to carry provisions to the inhabitants of the flooded town.

As a reward for the heroic defence of the previous year, the University of Leiden was founded by William I of Orange in 1575. Yearly on 3 October, the end

Year 696 was a leap year starting on Saturday of the Julian calendar. The denomination 696 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. St. Peter's Abbey is founded by bishop of Worms, at Salzburg. June 8 or 697 – Chlodulf, bishop of Metz August 13 – Takechi, Japanese prince Domnall Donn, king of Dál Riata Vinayaditya, king of Chalukya Woncheuk, Korean Buddhist monk

Johann Augustin Pucher was a Slovene priest, photographer and poet who invented an unusual process for making photographs on glass. Although his were not the first glass photographs, Pucher's process was unique, it was the only 19th-century photography technique, not based on expensive silver halide chemistry but was still sensitive enough to use in a camera, with exposure times comparable to those of the daguerreotype and calotype. Modern testing of Pucher's photographs has confirmed their chemically unusual nature. However, his process was never commercialized, attempts to recreate it based on published information have been unsuccessful. Pucher was born in Kranj on 26 August 1814. At the time, the present-day Slovenia was part of the Austrian Empire and was called the Duchy of Carniola; as a schoolchild, Pucher was interested in art and the natural sciences chemistry and physics. He wanted to study art, but became a Catholic priest. However, he continued to experiment in photography and music.

When the French Academy of Sciences announced the invention of the daguerreotype on 19 August 1839, Pucher mastered the process, but it was too expensive, so he developed his own way of making photographs. On 19 April 1842, he invented a photographic process on glass that he called the hyalotype, or "svetlopis" in Slovene, his photos are called puharotypes, in his honor. The first report about his invention was published in the newspaper Carniolia in 1841. While living in Bled, Pucher met a French viscount, Louis de Dax, who wrote about him in the Parisian magazine La Lumière; the church moved Pucher to a small village, where his contacts abroad lessened. He became sick from the harmful substances used in his experiments and died at the age of 49. According to Pucher's records of his photographic process, he coated a small glass plate with a layer of light-sensitive sulfur, exposed it to iodine vapors, inserted the prepared plate into a camera, he poured mercury into a metal container, placed the mercury at the bottom of the camera, heated it from below.

He exposed the prepared plate to light for 15 seconds, mercury vapors coated the exposed places on the picture. Pucher fixed it by wrapping it with alcohol, he preserved the photo with varnish. The advantages of Pucher's procedure included a shorter exposure time, a positive image, the possibility of reproduction. Pucher was not the first to try to create photos on glass: A Frenchman, Abel Niépce de Saint-Victor, reported his own invention to the French Academy of Sciences in 1847, it was not until January 1851 that the Austrian Academy of Sciences published a report on Pucher's method. Known photos by Pucher kept in the National Museum of Slovenia and in the Museum of Architecture and Design in Ljubljana, are: Self-portrait, reproduction of a lost original, National Museum Self-portrait, original on glass, 10 x 12 cm, National Museum Portrait of a man, original on glass, 9.4 x 11.5 cm, National Museum Portrait of a woman, original on glass, 10.3 x 12.1 cm, National Museum Andrej Vavken in Cerklje na Gorenjskem, original on glass, 6.7 x 8.4 cm, Museum of Architecture and Design Portrait of the composer Andrej Vavken and the painter Ivan Franke, original on glass, 9.7 x 11.5 cm, private collection Bled island, colored photo reproduction of a graphic motif on paper, 6.5 x 5.1 cm, National Museum Last Supper, colored photo reproduction of a graphic motif on paper, 7.8 x 6 cm, National Museum Gregor Rihar in a boat in Bled, photo reproduction of a drawing on paper, 9.1 x 6.3 cm, National Museum Most of Pucher's photos have been lost, including: 2 sent to a scientific assembly in Ljubljana in 1849 4 sent to Viscount Louis de Dax Photographs sent to the Austrian Academy of Sciences Photographs presented at world exhibitions in London, New York, Paris Portraits of relatives destroyed during World War II Pucher wrote at least 15 poems in Slovene and 4 in German.

Some of them were put to music by known composers. In recognition of Pucher's contribution to the Slovene national identity and the development of photographic science, Slovenia declared 2014 to be Pucher's Year; the honorary patronage of the jubilee was approved by President Borut Pahor. A yearlong program of events in Slovenia and abroad was organized in cooperation with many municipalities and institutions to celebrate the 200th anniversary of his birth. Several items and locations are named after Pucher: Janez Pucher Award, given by the Photographic Federation of Slovenia for exceptional achievement in photography Puharotype, Pucher’s photo procedure Puharjeva ulica, a street in Ljubljana Puharjeva ulica, a street in Kranj Pucher Prize, given by the Janez Puhar Photo Society in Kranj Pucher Medal, given by the Janez Puhar Photo Society in Kranj for the best portrait at International Federation of Photographic Art exhibitions Media related to Janez Puhar at Wikimedia Commons Puhar.si A site dedicated to Pucher