The Marqueses de Santillana is a noble title in Spain, originating from the region of Santillana del Mar in Cantabria. The title was created in the 15th century and has been held by various noble families over the years. The title signifies a rank of nobility, often associated with land ownership and influence in Spanish society. The most notable figure associated with the title is Íñigo López de Mendoza, the 1st Marquis of Santillana, a prominent poet and politician during the Spanish Golden Age. His literary contributions, particularly in the form of sonnets, have left a lasting impact on Spanish literature and culture.