Martín de Azpilcueta, Spanish theologian and economist (d. 1586)
Martín de Azpilcueta (Azpilkueta in Basque) (13 December 1491 – 1 June 1586), or Doctor Navarrus, was an important Spanish canonist and theologian in his time, and an early economist who independently formulated the quantity theory of money in 1556.