Tampa is a U.S. city in Hillsborough County on the western coast of the U.S. state of Florida. Human habitation in the Tampa Bay area can be traced back thousands of years. The Manasota culture is the earliest documented group, spanning from about 500 B.C. until about 700 A.D., by which time it had evolved into the Safety Harbor culture. The Tocobaga and the Pohoy were of this culture, and these were the dominant tribes living along the northern shore of Tampa Bay when Spanish explorers arrived in the early 1500s. Though Spain claimed all of Florida as its possession, it could not successfully establish a settlement on the west coast and did not attempt to do so after the mid-1500s. However, European contact with native peoples spread diseases which devastated local populations.