Within Christianity, women religious, known as nuns or religious sisters, are found in Catholic, Eastern Orthodox, Anglican, and Lutheran traditions among others. Though the terms are often used interchangeably, "nuns" historically take solemn vows and live a life of prayer and contemplation in a monastery or convent, while "sisters" take simple vows and live an active vocation of prayer and charitable works in areas such as education and healthcare. Examples include the monastic Order of Saint Clare founded in 1212 in the Franciscan tradition, or the Missionaries of Charity founded in 1950 by Mother Teresa to care for people living in grave poverty.