The view of homosexuality as a psychological disorder has been seen in literature since research on homosexuality first began; however, psychology as a discipline has evolved over the years in its position on homosexuality. Current attitudes have their roots in religious, legal, and cultural underpinnings. Some Ancient Near Eastern communities, such as the Israelites, had strict codes forbidding homosexual activity, and this gave way to later usage of the same texts by the original missionaries of Christianity, who themselves descended from the tribes of Israel; Paul in particular is notable for his allusion to and reinforcement of such texts in his letters to nascent churches. Later, the Apostolic Fathers and their successors continued to speak against homosexual activity whenever they mentioned it in their (surviving) writings. In the early Middle Ages the Christian Church ignored homosexuality in secular society; however, by the end of the 12th century, hostility towards homosexuality began to emerge and spread through Europe's secular and religious institutions. There were official expressions condemning the "unnatural" nature of homosexual behavior in the works of Thomas Aquinas and others. Until the 19th century, homosexual activity was referred to as "unnatural, crimes against nature", "sodomy" or "buggery" and was punishable by law, sometimes by death.