[4] On 29 April 1618, he was consecrated bishop by Giovanni Garzia Mellini, Cardinal-Priest of Santi Quattro Coronati with Francesco Sacrati (cardinal), Titular Archbishop of Damascus, and Cesare Ventimiglia, Bishop of Terracina, Priverno e Sezze, serving as co-consecrators.
[5] On 28 November 1633, he was appointed during the papacy of Pope Urban VIII as Bishop of Barcelona.
When the President of the Generalitat de Catalunya started negotiations with France to hand over the principality to create an independent Catalan Republic under a French protectorate, Gil Manrique tried in vain to change his mind.
The Spanish King reacted by sending troops to Catalonia and ordered Gil Manrique to use force against the rebels.
But Gil Manrique refused, and was dismissed and replaced by the Marquis de los Vélez.