The word "Saracen" was commonly used in medieval Europe to refer to a person who lived in or near what the ancient Romans knew as Arabia Petraea and Arabia Deserta. Its original meaning in Greek and Latin is not known with certainty. By the early medieval period, it had come to be associated with the Arabian tribes. Following the rise of Islam, which occurred in Arabia, the word's definition evolved to refer not only to Arabs, but to Muslims taken generally as well. It eventually became the standard adjective among European Christians for all people and things from the Muslim world, regardless of whether they were Arab in origin.