When referring to Roman Catholic religious orders, the term Second Order refers to those Orders of cloistered nuns which are a part of the mendicant Orders that developed in the Middle Ages.
In early 13th century, St. Dominic Guzman was a canon regular at the Cathedral of Osma in Spain. He accompanied his bishop on a trip to Denmark to arrange a marriage between the son of the King of Castile and a member of the Danish royal family. On the return trip, Dominic encountered the followers of the Duke of Albi in southern France. The Duke was a leading Cathar, which embraced a gnostic form of Christianity. Dominic undertook a preaching campaign to them, in order to bring them back to an orthodox understanding of the faith.
Several women who responded to his preaching sought a completely new direction in their lives. In response to this, Dominic established a house for them in 1206, where they could lead lives of prayer and penance. When he came to found his Order of men, which was to become the Dominican friars in 1214, the women were established as nuns and a full part of the Order. As women, however, they were not free to go about and preach, as were the men.
St. Francis of Assisi began his life of preaching and penance in the Tuscan region of Italy around this same time. His preaching drew a young noblewoman of the city, the Lady Clare to be inspired to follow his way of life. Determined to take this step, Clare snuck out of her family's palace to join Francis and his brothers on the night of Palm Sunday 1211. After receiving her commitment and giving her the Franciscan habit, Francis then entrusted Clare to the care of a nearby community of Benedictine nuns for her training in monastic life. The Order that emerged from her commitment, originally called the "Poor Ladies of Assisi" and now known as the Poor Clares, took a form of monastic life committed to a strict life of poverty.