The Duke of Coimbra is a noble title in the Portuguese nobility, historically associated with the city of Coimbra. The title was first created in the 14th century and has been held by various members of the Portuguese royal family. The Duke often played significant roles in the political and military affairs of Portugal. The title is linked to the House of Aviz, which was a prominent royal house in Portugal. The most notable Duke of Coimbra was Infante Pedro, who was a key figure during the 1383-1385 Crisis, a pivotal moment in Portuguese history that helped secure the country's independence from Castile.