John, Knights of St., a religious order of knights, founded in 1048, and instituted properly in 1110, for the defence of pilgrims to Jerusalem; established a church and a cloister there, with a hospital for poor and sick pilgrims, and were hence called the Hospital Brothers of St. John of Jerusalem; the knights consisted of three classes, knights of noble birth to bear arms, priests to conduct worship, and serving brothers to tend the sick; on the fall of Jerusalem they retired to Cyprus, conquered Rhodes, and called themselves Knights of Rhodes; driven from which they settled in Malta and took the name of Knights of Malta, after which the knighthood had various fortunes.
Definition taken from The Nuttall Encyclopædia, edited by the Reverend James Wood (1907)
John, Epistles of * John, Prester