The history of the Catholic Church is traced by the Catholic Church back to apostolic times and thus covers a period of nearly 2,000 years, making it one of the world's oldest institutions. The history of the Catholic Church is an integral part of the history of Christianity and of Western civilization. The whole period of the next five centuries was dominated by the struggle between Christianity and Islam throughout the Mediterranean Basin. The battles of Poitiers, and Toulouse preserved the Catholic west, even though Rome itself was ravaged in 850, and Constantinople besieged.