In the Roman Empire, the town was known as Portus Victoriae Iuliobrigensium. Its present name is derived from St Emeterio, according to legend a martyr whose head was brought there in the 3rd century. In 1187, King Alfonso VIII made the abbot of San Emeterio lord of the town, and in 1248 Santander participated in the battle for Seville, receiving a coat of arms as reward.
Santander was an important port for Castile in the later Middle Ages, and also for trade with the New World. It officially became a city in 1755.
In 1893 the freighter Cabo Machichaco exploded in the harbor, killing 500 people. Santander became the favored summer location for King Alfonso XIII, and it remains popular for vacations, although a fire in 1941 destroyed much of the old part of the city.
Santander is a department of Colombia. See Santander Department.
Francisco de Paula Santander was an important South American independentist, Vicepresident of the Republic of Greater Colombia, and President of the Republic of New Granada.