A castle is a type of fortified structure built during the Middle Ages predominantly by the nobility or royalty and by military orders. Scholars debate the scope of the word castle, but consider it to be the private fortified residence of a lord or noble; this is distinct from a palace, not fortified. Usage of the term has varied over time and has been applied to structures as diverse as hill forts and country houses. Over the 900 years that castles were built, they took on a great many forms with many different features, although some, such as curtain walls and portcullises, were commonplace. European-style castles originated in the 9th and 10th centuries, after the fall of the Carolingian Empire resulted in its territory being divided among individual lords and princes; these nobles built castles to control the area surrounding them and the castles were both offensive and defensive structures. Although their military origins are emphasised in castle studies, the structures served as centres of administration and symbols of power.

Urban castles were used to control the local populace and important travel routes, rural castles were situated near features that were integral to life in the community, such as mills, fertile land, or a water source. Many northern European castles were built from earth and timber, but had their defences replaced by stone. Early castles exploited natural defences, lacking features such as towers and arrowslits and relying on a central keep. In the late 12th and early 13th centuries, a scientific approach to castle defence emerged; this led with an emphasis on flanking fire. Many new castles were polygonal or relied on concentric defence – several stages of defence within each other that could all function at the same time to maximise the castle's firepower; these changes in defence have been attributed to a mixture of castle technology from the Crusades, such as concentric fortification, inspiration from earlier defences, such as Roman forts. Not all the elements of castle architecture were military in nature, so that devices such as moats evolved from their original purpose of defence into symbols of power.

Some grand castles had long winding approaches intended to dominate their landscape. Although gunpowder was introduced to Europe in the 14th century, it did not affect castle building until the 15th century, when artillery became powerful enough to break through stone walls. While castles continued to be built well into the 16th century, new techniques to deal with improved cannon fire made them uncomfortable and undesirable places to live; as a result, true castles went into decline and were replaced by artillery forts with no role in civil administration, country houses that were indefensible. From the 18th century onwards, there was a renewed interest in castles with the construction of mock castles, part of a romantic revival of Gothic architecture, but they had no military purpose; the word castle is derived from the Latin word castellum, a diminutive of the word castrum, meaning "fortified place". The Old English castel, Old French castel or chastel, French château, Spanish castillo, Portuguese castelo, Italian castello, a number of words in other languages derive from castellum.

The word castle was introduced into English shortly before the Norman Conquest to denote this type of building, new to England. In its simplest terms, the definition of a castle accepted amongst academics is "a private fortified residence"; this contrasts with earlier fortifications, such as Anglo-Saxon burhs and walled cities such as Constantinople and Antioch in the Middle East. Feudalism was the link between a lord and his vassal where, in return for military service and the expectation of loyalty, the lord would grant the vassal land. In the late 20th century, there was a trend to refine the definition of a castle by including the criterion of feudal ownership, thus tying castles to the medieval period. During the First Crusade, the Frankish armies encountered walled settlements and forts that they indiscriminately referred to as castles, but which would not be considered as such under the modern definition. Castles served a range of purposes, the most important of which were military and domestic.

As well as defensive structures, castles were offensive tools which could be used as a base of operations in enemy territory. Castles were established by Norman invaders of England for both defensive purposes and to pacify the country's inhabitants; as William the Conqueror advanced through England, he fortified key positions to secure the land he had taken. Between 1066 and 1087, he established 36 castles such as Warwick Castle, which he used to guard against rebellion in the English Midlands. Towards the end of the Middle Ages, castles tended to lose their military significance due to the advent of powerful cannons and permanent artillery fortifications. A castle could act as a stronghold and prison but was a place where a knight or lord could entertain his peers. Over time the aesthetics of the design became more important, as the castle's appea

Laurentian, or St. Lawrence Iroquoian, was an Iroquoian language spoken until the late 16th century along the shores of the Saint Lawrence River in present-day Quebec and Ontario, Canada, it is believed to have disappeared with the extinction of the St. Lawrence Iroquoians as a result of warfare by the more powerful Mohawk from the Haudenosaunee or Iroquois Confederacy to the south, in present-day New York state of the United States; the explorer Jacques Cartier observed in 1535 and 1536 about a dozen villages in the valley between Stadacona and Hochelega, the sites of the modern cities of Quebec City and Montreal. Archeologists have unearthed other villages farther west, near the eastern end of Lake Ontario. St. Lawrence Iroquoians lived in villages which were located a few kilometres inland from the Saint-Lawrence River, were enclosed by a wooden palisade. Up to 2000 persons lived in the larger villages. By the time the explorer Samuel de Champlain arrived in 1608, however, he found no trace of the Iroquoians visited by Jacques Cartier some 75 years earlier.

Scholars have developed several theories to explain the complete disappearance of the St. Lawrence Iroquoians, among them devastating wars waged by the Mohawk from the south, epidemics of Old World infectious diseases, or migration towards the Great Lakes region. Archeological evidence points most to devastating wars with neighbouring Iroquoian tribes, the Huron and the nations of the Iroquois League the Mohawk. Several dialects of Laurentian may have existed in the 16th century in the St. Lawrence River valley; the sparse records made by Jacques Cartier during his voyages cannot be considered conclusive, the Laurentians may have spoken several distinct languages. A few Laurentian words are still in use today as toponyms: most notably the word canada, meaning "village" in Laurentian. Jacques Cartier used the river that crosses it; the name of Donnacona, the Iroquoian chieftain Cartier met at Stadacona, remains in use as the name of the town of Donnacona, Quebec. Hochelaga remains in use in the Montreal borough of Hochelaga-Maisonneuve and the alternate spelling "Osheaga" serves as the name of Montreal's annual Osheaga Festival.

On the basis of the Laurentian vocabularies of Cartier, the linguist Marianne Mithun concludes that Laurentian was an Iroquoian language, its speakers were "clearly in contact with the Lake Iroquoian peoples ". In 1545 Jacques Cartier published a journal of his voyages, including the first list of Laurentian words. Here are some examples, as written by Cartier: A second shorter vocabulary list was appended to his journal of his first voyage, published much first in Italian and in English and French. List of Web sites on the Laurentian language Laurentian words

MIL-DTL-5015 is a United States Military Standard which covers heavy-duty circular electrical connectors with soldered or crimped contacts. They are used for both digital and analog signals, as well as power distribution, are common in various fields, including defense and industrial machinery; the connectors are versatile and reliable, due to their prevalence inexpensive. Many manufacturers have created connectors based on MIL-DTL-5015 and MIL-C-5015, most notably Amphenol and ITT Corporation; these connectors are available as off-the-shelf products for end users, as well as "mil-COTS" products for military use. In the early 1930s, Cannon was contracted by Douglas Aircraft Company to develop electrical circular connectors for use on the DC-1 and on the subsequent DC-2 and DC-3 aircraft platforms; this led to the release of the original AN9534 standard in 1939, the precursor to MIL-C-5015. During the late 1930s, Cannon's Type AN series set the standard for modern circular connectors, in 1949, MIL-C-5015 was specified.

It was revised in 1958, 1971, 1976. The final revision, released in March 1994, was MIL-C-5015G. In May 2000, MIL-C-5015G was superseded by six years after its publication. In December 2009, MIL-DTL-5015 was superseded by SAE-AS50151, pursuant to the general United States Department of Defense goal to reduce the number of military standards in favor of industry technical standards supported by standards organizations. Whilst the original military standard is no longer in use the family of connectors continues to be called MIL-DTL-5015 or MIL-C-5015 by manufacturers and users. MIL-DTL-5015 connectors are used for many situations where mechanical and electrical reliability is important; this includes civil applications, as well as military applications. The main advantages of MIL-DTL-5015 connectors are as follows: Ease of engagement and disengagement Compatibility different types and numbers of contacts, allowing power and signal lines in one connector Wide range of allowable contact voltages and currents Rugged mechanical performance under harsh environmental conditions Variety of materials and finishes Wide temperature range Resistance to vibration and mechanical shock Relatively low price Interlock and captive nut to prevent inadvertent disassembly Several shell styles One significant drawback is the inefficient use of panel surface area when used in arrays, compared to rectangular connector housings.

The fine thread is prone to mechanical damage and can be time consuming to tighten. Another disadvantage to MIL-DTL-5015 connectors is that they have only one keyway, unlike some connector specifications, such as MIL-DTL-38999; this limits the connectors' ability to be polarized to prevent mis-mating of same-shell-size connectors in an area where multiple sets of plugs and receptacles exist. Limited polarization is available in certain insert configurations, which relies on the pins bottoming out on the opposing connector face to prevent engagement. Connectors with multiple keyways can be polarized so that the shells prevent engagement of the pins on mis-mated connectors entirely. There are 19 shell sizes with about 160 approved insert arrangements incorporating 1-85 contacts; the circular connectors are available with a choice of wall mount, box mount, cable connecting and jam-nut receptacles, as well as standard or self-locking plugs. MIL-C-5015 specifies four discrete product categories known as series.

Connectors from each of the first three series are compatible, their individual components differ: It refers to classes of connectors, which specify products in more detail: Several manufacturers have created derivative circular connectors that intermate with the military versions designed to MIL-C-5015 and/or MIL-DTL-5015. Commercial variants and military-style connectors are sometimes called Type AN connectors, MS connectors, or Amphenol connectors. Similar connectors with different contact arrangements and bayonet coupling rings are available to military specifications. A wide range of MIL-DTL-5015 connectors are available on the market, with specifications and drawings supplied. In 1998, the AMP Incorporated brand-owned manufacturing plant was acquired by Amphenol and listed under the Amphenol-Aerospace Group; the plant continues to produce upgraded MIL-C-5015 connectors with crimp contacts with rear contact removal. Mil Spec Connectors: Circular - summary of relevant standards MIL-DTL-5015 Rev.

H - the latest revision of MIL-DTL-5015H SAE AS50151 - the current equivalent of MIL-DTL-5015