Lope de Barrientos (Medina del Campo, Spain, 1382 - Cuenca, Spain, 1469), sometimes called Obispo Barrientos ("Bishop Barrientos"), was a powerful clergyman of the Spanish Crown of Castile during the 15th century, although his prominence and the influence he wielded during his lifetime is not well-represented in Spanish history.
From relatively humble beginnings in Medina del Campo where he studied grammar, he took advantage of a secular custom of Castilian monarchs to selectively promote lower class court nobility to enter the service of Ferdinand I of Aragon; a capacity normally reserved only to those of high birth.
Later, using his native intelligence, Barrientos exploited every opening to climb in social rank against the backdrop of a complex political atmosphere: over his lifetime he became a Dominican friar; served as a professor of theology at the University of Salamanca (possibly the first); as the bishop of three successive cities—Segovia, Ávila, and chiefly of Cuenca —as royal confessor of John II of Castile; an Inquisitor; an advisor to Henry IV of Castile; and as Chancellor of Castile. In addition, he published a series of theological treatises and tracts concerning religious problems encountered in 15th century Spain.