A courtesan, in modern usage, is a euphemism meaning an escort, mistress or a prostitute, for whom the art of dignified etiquette is the means of attracting wealthy, powerful, or influential clients. The term originally meant a courtier, a person who attends the court of a monarch or other powerful person.
In feudal society, the court was the centre of government as well as the residence of the monarch, and social and political life were often completely mixed together. Prior to the Renaissance, courtesans served to convey information to visiting dignitaries, when servants could not be trusted. In Renaissance Europe, courtiers played an extremely important role in upper-class society. As it was customary during this time for royal couples to lead separate lives—commonly marrying simply to preserve bloodlines and to secure political alliances—men and women would often seek gratification and companionship from people living at court. In fact, the verb 'to court' originally meant "to be or reside at court", and later came to mean "to behave as a courtier" and then 'courtship', or "to pay amorous attention to somebody". The most intimate companion of a ruler was called the ”favourite”.
In Renaissance usage, the Italian word cortigiana, feminine of cortigiano ("courtier") came to refer to a person who attends the court, and then to a well-educated and independent woman, eventually a trained artist or artisan of dance and singing, especially one associated with wealthy, powerful, or upper-class society who was given luxuries and status in exchange for entertainment and companionship. The word was borrowed by English from Italian through the French form courtisane during the 16th century, especially associated to the meaning of donna di palazzo.
A male figure comparable to the courtesan was the Italian cicisbeo, the French chevalier servant, the Spanish cortejo or estrecho.
The courtesans of East Asia, particularly those of the Japanese empire, held a different social role than that of their European counterparts. Examples of Japanese courtesans included the oiran class, who were more focused on the aspect of entertainment in comparison with European courtesans.
One type of courtesan was known (in Italy) as the cortigiana onesta, or the honest courtesan, who was cast as an intellectual. Another was the cortigiana di lume, a lower class of courtesan. The former was the sort most often romanticized and treated more-or-less equal to women of the nobility. It is with this type of courtesan that the art of "courtisanerie" is best associated.
The cortigiane oneste were usually well-educated and worldly (sometimes even more so than the average upper-class woman), and often held simultaneous careers as performers or artists. They were typically chosen on the basis of their "breeding"—social and conversational skills, intelligence, common-sense, and companionship—as well as their physical attributes. It was usually their wit and personality that set them apart from regular women. Sex constituted only a facet of the courtesan's array of services. For example, they were well-dressed and ready to engage and participate in a variety of topics ranging from art to music to politics.
In some cases, courtesans were from well-to-do backgrounds, and were even married—but to husbands lower on the social ladder than their clients. In these cases, their relationships with those of high social status had the potential to improve their spouses' status—and so, more often than not, the husband was aware of his wife's profession and dealings.