(called da Siena), a Portuguese biographer and theologian, was born at Guimaraes, Portugal. The name of his family was La Conception. He completed his studies at Lisbon and Coimbra. went to the Netherlands, and was made doctor at Louvain. He afterwards went to Brittany, where he remained some time with don Antonio, who assumed the title of king of Portugal. Antonio da Siena afterwards went to Rome. He died in 1586, having published notes upon the Summa of St. Thomas, and some other works, such as the Annals and the Bibliotheca of the authors of his order who wrote upon morality and spirituality (Paris, 1647). See Hoefer, Nouv. Biog. Generale, s.v.