In 1494 the armies of the French king, Charles VIII, invaded Italy to capture the kingdom of Naples. They swept through the country and bombarded and destroyed many castles. This invasion signaled the end of the castle as a stronghold of defense. For centuries it had been the dominant fortification in Western Europe for the defense of kings, nobility, and townspeople. Ancient cities were often walled to keep out invaders, and within the walls there was usually a citadel, a strongly built fortification occupying the highest or militarily most advantageous position. A castle is much like such a walled city and its citadel contracted into a smaller space. Castles were basically fortified locations. The word itself comes from the Latin castellum.
Up to the 6th century fortifications were primarily communities in which most of the population lived. But in the middle of the 6th 
century, the armies of the Byzantine Empire began to build strong forts as defensive positions. For the next few centuries this castle building was confined to the Byzantine Empire, but later hordes of Islamic warriors who swept out of Arabia to conquer the Middle East, North Africa, and much Byzantine territory also started building such forts. Western Europe, in the depths of the Dark Ages from the 5th through the 9th century, had no such works. But late in the 9th century, as local lords and kings began to consolidate power, castle building began probably in France. Once begun, castle building spread rapidly to other areas. But it was not until the 12th and 13th centuries, after the Crusaders returned from their wars against Islam in Palestine, that castles as imposing as those of the Byzantine or Islamic empires were constructed in Europe.
Many of the stone castles of the late Middle Ages still stand. Some are tourist attractions, in various states of repair, along the Rhine River from Mainz to Cologne in Germany, dotted about the French countryside, or perched on hilltops in Spain. The original French castles had been built on open plains. Later ones, however, were situated on rocky crags, at river forks, or in some position where advancing enemies would find approach extremely difficult, if not impossible. The fortifications became more elaborate with time, with considerable attention paid to making the living quarters more comfortable. A typical castle was usually guarded on the outskirts by a surrounding heavy wooden fence of sharp-pointed stakes called a barbican.. It was intended to prevent surprise attacks by delaying the advance of assailants and giving those within the castle compound time to prepare to resist and attack. Inside the barbican stretched the lists, or wards: strips of land that encircled the castle. The lists served as a road in time of peace and as a trap in war; once within the barbican the enemy was in the range of arrows shot from the castle walls. In peacetime the lists also served as an exercise ground for horses and occasionally as tournament grounds.
Between the lists and the towering outer walls of the castle itself was the moat, usually filled with water. Across it stretched a 
drawbridge, which was raised every night. At the castle end of the drawbridge was the portcullis, a large sliding door made of wooden or iron grillwork hung over the entryway. It moved up and down in grooves and was raised every day and lowered at night. In times of danger it blocked the way to the heavy oak gates that served as doors to the castle compound. These gates were so large that they were rarely opened except on ceremonial occasions. A smaller door was built into one of them to provide easy entrance and exit for those who lived in the castle.. A person known as the chief porter was charged with the responsibility of making sure that only friends passed through. The outer walls of most castles were massively thick, sometimes as much as 15 feet. At intervals were high towers, each a small fort in itself with provisions to withstand a long siege. When an attack was expected, wooden balconies were hung over the outer edges of the wall. During an attack, large stones were thrown or boiling oil poured from the balconies onto anyone trying to climb the wall. The wall and the towers had hundreds of narrow openings through which defenders could shoot arrows and other missiles. Inside the walls was the bailey, or courtyard. At intervals around the bailey were the stables, a carpentry shop, the shop of the armorer and blacksmith, barracks for the men-at-arms and for servants, a chapel, and a storehouse. There was also an oven room where the bread was baked, a kitchen, a kennel for dogs, and a well and drinking fountain.. The largest building along the wall was the castle owner’s home. It contained the apartment for the master and his family and a great hall. This great hall was the center of social life such as wedding feasts, banquets, and knighting ceremonies. Within the walls there was another structure called the keep, or donjon (dungeon).. The keep was the focal point of the castle, the place to which, in times of attack or siege, the whole population of the castle retired if the outer defenses were failing. The keep had its own walls and was often protected by a moat as well. It contained private apartments, service rooms, weapons supplies, and a well to provide water.
Most keeps were rectangular structures from two to four stories high. The entrance doorway was often on the second floor, with access by a stairway protected by a wall or forebuilding. In the Middle East the Crusaders from Europe found keeps that were built with round or multiangular towers to defend them more easily against an enemy coming from any direction. The round keep became common in Europe after the 12th century. Some later castles were built in a square and enclosed by one or two lines of walls. At each corner of the inner line of walls was a strong tower. Powerful gateways took the place of the keep, and great care was taken in building the outerworks to make access to the castle difficult. The castles of Conway and Caernarvon in Wales are both of this type. The terms castle and palace have often been used interchangeably, but they are not the same. Castles are fortifications, while palaces have been built for centuries as residences for kings and nobles.. But as castles began to lose their defensive role, they became residences; and to them were added the customary luxuries. As early as the 15th century, imposing residential tower houses, designed more for elegance than defense, were built within castles, such as those at Vincennes near Paris and Tattershall in England. Historically the palace antedates the castle by several centuries. Although the word derives from the Palatine Hill in Rome, where the emperors built their residences, palaces were built for the pharaohs of ancient Egypt as early as the 16th century BC. Much larger than the Egyptian palaces were those built in Assyria, which today is Iraq. The palace at Khorsabad of Sargon II, who ruled from 721 to 705 BC, extended over more than 25 acres. In Rome more than 1 million square feet of the Palatine Hill were devoted to splendid residences of such emperors as Augustus, Tiberius, and Septimius Severus. Palace building declined in Europe during the Middle Ages until prosperity and a measure of safety returned during the Renaissance. Then, in Italy, every prince and wealthy family had its palazzo. Many are still standing: the Pitti and Medici palaces in Florence and the palaces along the Grand Canal in Venice. London has three notable palaces: Buckingham, Whitehall, and St. James. Many German cities notably Wurzburg and Munich have impressive palaces. Among those most recently built are those of Ludwig II of Bavaria in the 19th century.
The most famous and most frequently pictured is Neuschwanstein, located near Fussen. But for many the most appealing is the small Linderhof, a jewel of rococo design near Oberammergau. Ludwig’s Herrenchiemsee palace on an island in the lake named Chiemsee was modeled after Louis XIV’s magnificent edifice at Versailles, near Paris. Versailles has other imitations, including the beautiful Schonbrunn Palace in Vienna. Palaces will probably be built for as long as there is wealth enough to pay for them. In the 1980s the sultan of Brunei, Sir Muda Hassanal Bolkiah Muizzaddin Waddaulah, opened his new palace. Named New Istana, it contains 1,788 rooms, making it one of the grandest palaces anywhere. Although castles are no longer readily built, because of the lack of money or just the lack of need, they will always be appreciated for their beauty, architecture, and most importantly the land that they helped to defend.
Works Cited
.Smith, Beth. Castles. p.18. New York: Franklin Watts, 1988. .Macaulay, David. Castle. p.54. Boston: Houghton Mifflin Company, 1977. .Clements, Gillian. The Truth about Castles. p.9. Minneapolis: Carolrhoda Books, Inc., 1990. .Macaulay, David. Castle. p.13. Boston: Houghton Mifflin Company, 1977. .Smith, Beth. Castles. p. 23. New York: Franklin Watts, 1988.
very helpful thanks!