The term “magic” etymologically derives from the Greek word mageia (μαγεία). In ancient times, Greeks and Persians had been at war for centuries, and the Persian priests, called magosh in Persian, came to be known as magoi in Greek. Ritual acts of Persian priests came to be known as mageia, and then magika—which eventually came to mean any foreign, unorthodox, or illegitimate ritual practice. The first book containing explanations of magic tricks appeared in 1584. During the 17th century, many similar books were published that described magic tricks. Until the 18th century, magic shows were a common source of entertainment at fairs. A founding figure of modern entertainment magic was Jean Eugène Robert-Houdin, who had a magic theatre in Paris in 1845. John Henry Anderson was pioneering the same transition in London in the 1840s. Towards the end of the 19th century, large magic shows permanently staged at big theatre venues became the norm. As a form of entertainment, magic easily moved from theatrical venues to television magic specials. Performances that modern observers would recognize as conjuring have been practiced throughout history. For many recorded centuries, magicians were associated with the devil and the occult. During the 19th and 20th centuries, many stage magicians even capitalized on this notion in their advertisements. The same level of ingenuity that was used to produce famous ancient deceptions such as the Trojan Horse would also have been used for entertainment, or at least for cheating in money games. They were also used by the practitioners of various religions and cults from ancient times onwards to frighten uneducated people into obedience or turn them into adherents. However, the profession of the illusionist gained strength only in the 18th century, and has enjoyed several popular vogues since.