Against All Heresies was written at the request of Spanish merchants of Flanders to combat heretics and was first published in Paris in 1534. It is a description and criticism of more than 400 heresies, which had arisen in the Church since the time of the Apostles, presented in alphabetical order. It was the author's most popular work for which he received the nickname, "the scourge of heretics." King Philip II of Spain, whom the author served as chaplain, wrote in the preface of this work that this book is "such a useful and beneficial book for the Christian state." St. Robert Bellarmine drew from it in writing his Controversies.

The author, Alphonsus a Castro, born at Zamora, Spain, was admitted into the Order of St. Francis at Salamanca. He was one of the most celebrated preachers of his time; and his merit procured him the esteem of Charles V and Philip II. He attended Philip II when that prince went to England to marry the queen. Afterwards he made a long stay in the Low Countries; and he was there still when the king of Spain nominated him to the Archbishopric of Compostella. But before he received his Bulls, he died at Brussels the 15th of February, 1558, at sixty-three years of age. Alfonso Garc