Tomás Fernández de Medrano

Tomás Fernández de Medrano (died 1616) was a Spanish nobleman, lord and divisero of Valdeosera and Regajal, author, theologian, and philosopher from Entrena, who served as a prominent adviser, counselor, statesman, diplomat, and courtier to Philip II and Philip III of Spain. He also served as a counselor and Secretary of State and War for Charles Emmanuel I, Duke of Savoy, and Princess Catherine Micaela of Spain.

He later served in the same capacity for the Princes of Savoy. As lord and divisero of Valdeosera, Medrano was appointed mayor, chief magistrate, and lord of Valdeosera in San Román de Cameros. He was also a Knight of the Sovereign Order of Saint John of Jerusalem, manager for the Grand Prior of Castilla San Juan, and The Most Reverend Master and Patron of the convent of Saint John of Acre in Salinas de Añana. In addition to his other roles, Medrano was the Secretary of the Holy Chapters and Assemblies of Castile. He also served for eight years under Enrique de Guzmán, 2nd Count of Olivares, and as secretary to Prince Giovanni Andrea Doria, from 1579 to 1581. In 1605, he translated and printed a brief from Pope Paul V in Latin and Spanish for King Philip III of Spain and the Order of Saint John.

He became a key figure in the political affairs of the Duchy of Savoy and the Spanish monarchy. He is best known for República Mista, published at the royal press in 1602 and dedicated to the Duke of Lerma, the first valido of Philip III. Although only the first part was printed, it shaped early seventeenth-century political thought. In 1617, Fray Juan de Salazar adopted Medrano's treatise and doctrine to present the Spanish monarchy as guided by virtue and reason yet bound by divine and natural law. The doctrine was upheld under Philip II, codified under Philip III, and practiced by their court.