Chivalry is a term relating to the medieval institution of knighthood . It is usually associated with ideals of knightly virtues, honor and courtly love. Today, the terms chivalry and chivalrous are used to describe courteous behavior, especially that of men towards women.

The medieval knightly class was adept at the art of war, trained in fighting in armor, with horses, lances, swords and shields. Knights were taught to excel in the arms, to show courage, to be gallant, loyal and to swear off cowardice and baseness.

Related to chivalry was the practice of heraldry and its elaborate rules of displaying coats of arms. When not fighting, chivalric knights typically resided in a castle or fortified house, while some knights lived in the courts of kings, dukes and other great lords. The skills of the knight carried over to peacetime activities such as the hunt and tournament .

The tradition of the chivalric "knight in shining armor" can be traced back to the Arabs, with notable pre-Islamic figures like the Bedouin knight Antar The Lion (580 CE). He is believed to be the model of this tradition. Charles Reginald Haines noted traits "such as loyalty, courtesy, ...are found in eminent degree among the Arabs." Medieval Spain, which he calls the "cradle of chivalry", could bear that pre-modern title, due to the direct impact of Arab civilization in al-Andalus.

"Piety, courtesy, prowess in war, the gift of eloquence, the art of poetry, skill on horseback, dexterity with sword, lance, and bow" was expected of the elite Moorish knight.

Richard Francis Burton, when characterizing this strain of thought in the writings of Europe as a whole, maintained "were it not evident that the spiritualising of sexuality by imagination is universal among the highest orders of mankind", he continues, "I should attribute the origins of love to the influences of the Arabs' poetry and chivalry upon European ideas rather than to medieval Christianity." The frequent clashes between the Christians and Muslims preceding the Christian Crusades leave no doubt that orders of the knighthood and the tradition of courtly love were transmitted into Europe by way of the Muslim occupation

Christianity had a modifying influence on the virtues of chivalry. The Peace and Truce of God in the 10th century was one such example, with limits placed on knights to protect and honor the weaker members of society and also help the church maintain peace. At the same time the church became more tolerant of war in the defense of faith, espousing theories of the just war; and liturgies were introduced which blessed a knight's sword, and a bath of chivalric purification.

In the 11th century the concept of a "knight of Christ" ( miles Christi ) gained currency in France, Spain and Italy. These concepts of "religious chivalry" were further elaborated in the era of the Crusades, with the Crusades themselves often being seen as a chivalrous enterprise. Their ideas of chivalry were also further influenced by Saladin, who was viewed as a chivalrous knight by medieval Christian writers.

The relationship between knights and the nobility varied based on region. In France being dubbed a knight also bestowed noble status. In Germany and the Low Countries, knights and the nobility were distinctly different classes. In England, the relations between knights, nobles and land-owning gentry were complex.

In the later Middle Ages, wealthy merchants strove to adopt chivalric attitudes - the sons of the bourgeoisie were educated at aristocratic courts where they were trained in the manners of the knightly class. This was a democratization of chivalry, leading to a new genre called the courtesy book, which were guides to the behavior of "gentlemen". Thus, the post-medieval gentlemanly code of the value of a man's honor, respect for women, and a concern for those less fortunate, is directly derived from earlier ideals of chivalry and historical forces which created it.