Juan Martínez Silíceo (1486–1557) was a Spanish Roman Catholic bishop, cardinal and mathematician.

[1] He became a renowned mathematician for his time after publishing "Arithmética", firstly printed in Paris and afterwards all across Spain.

[1] He was buried in the church of the Colegio de Doncellas Nobles, a girls' school he had founded in Toledo.

[1] Siliceo successfully fought to impose the limpieza de sangre ("purity of blood") statutes on the Archdiocese of Toledo in order to exclude the Conversos, those Spaniards descended from Jews who had converted to Catholicism, from holding official positions within the Church hierarchy.

French scholar of Anti-Semitism, the late Leon Poliakov describes Siliceo as precursor of modern anti-semitic ideas: the idea that Christ appeared among the Jews because of their "perversity" and "as to the Jewish origins of the Mother of God, the theology of Siliceo simply ignored them...anticipating the 'Aryan Christ' of Nazi theology.