Antonio Agustín y Albanell (1516–1586), also referred to as Augustinus, was a Spanish Humanist historian, jurist, and Roman Catholic archbishop of Tarragona, who pioneered the historical research of the sources of canon law.

[1] Born in Zaragoza, Agustín studied law and classical literature in Alcalá, Salamanca, Padua and Bologna, notably as a pupil of Andrea Alciati.

With his nomination as an auditor of the Sacra Rota Romana in 1544, Agustín started his ecclesiastical career, which saw him become a papal nuncio in 1554/55.

Agustín is now primarily remembered as the first canon law historian; Peter Landau counts him among the other authors that enabled us to consider the 16th century the founding age of the science of history.

His first main work, Emendationum et opinionum libri IV, proposed the now widely accepted thesis that the Littera Florentina manuscript was the source for all other copies of the Pandects.