Puerto Rico's first inhabitants were the Taino Indians, who encountered Columbus in 1493. The Spanish quickly settled, defending their territory against the Dutch and British. This is evident by the imposing fortresses of Old San Juan, namely the El Morro Castle, dominating the old section of this capital city. In 1897, Spain declared Puerto Rico an autonomous state. Spain later ceded Puerto Rico to the U.S. and residents were granted American citizenship in 1917.