Sometimes called the patron saint of lost things, the New Advent website provides a helpful biography of St. Anthony. Here is an excerpt:
Later writers of the fifteenth century asserted that his father was Martin Bouillon, descendant of the renowned Godfrey de Bouillon, commander of the First Crusade, and his mother, Theresa Tavejra, descendant of Froila I, fourth king of Asturia. Unfortunately, however, his genealogy is uncertain; all that we know of his parents is that they were noble, powerful, and God-fearing people, and at the time of Ferdinand's birth were both still young, and living near the Cathedral of Lisbon.
Having been educated in the Cathedral school, Ferdinand, at the age of fifteen, joined the Canons Regular of St. Augustine, in the convent of St. Vincent, just outside the city walls (1210). Two years later to avoid being distracted by relatives and friends, who frequently came to visit him, he betook himself with permission of his superior to the Convent of Santa Croce in Cóimbra (1212), where he remained for eight years, occupying his time mainly with study and prayer. Gifted with an excellent understanding and a prodigious memory, he soon gathered from the Sacred Scriptures and the writings of the Holy Fathers a treasure of theological knowledge.
You can read the whole thing here.