Mother Teresa (1910-1997), known in the Catholic Church as Saint Teresa of Calcutta, was an Albanian-Indian Roman Catholic nun and missionary. 

In 1950 Teresa founded the Missionaries of Charity, a Roman Catholic religious congregation which had over 4,500 sisters and was active in 133 countries in 2012. The congregation manages homes for people dying of HIV/AIDS, leprosy and tuberculosis; soup kitchens; dispensaries and mobile clinics; children's- and family-counseling programs; orphanages, and schools. Members, who take vows of chastity, poverty, and obedience, also profess a fourth vow: to give "wholehearted free service to the poorest of the poor"