Thomas Cajetan
Thomas Cajetan ( KAJ-ə-tən; 20 February 1469 – 9 August 1534), also known as Gaetanus or Cajetanus, commonly Tommaso de Vio or Thomas de Vio, was an Italian philosopher, theologian, the Master of the Order of Preachers 1508 to 1518, and cardinal from 1517 until his death. He was a leading theologian of his day who is now best known as the spokesman for Catholic opposition to the teachings of Martin Luther and the Protestant Reformation while he was the Pope's legate in Augsburg, and among Catholics for his extensive commentary on the Summa Theologiae of St.