The area of the modern city of Jacksonville has been inhabited for thousands of years. On Black Hammock Island in the national Timucuan Ecological and Historic Preserve, a University of North Florida team discovered some of the oldest remnants of pottery in the United States, dating to 2500 BC. In the 16th century, the beginning of the historical era, the region was inhabited by the Mocama, a coastal subgroup of the Timucua people. At the time of contact with Europeans, all Mocama villages in present-day Jacksonville were part of the powerful chiefdom known as the Saturiwa, centered around the mouth of the St. Johns River. One early map shows a village called Ossachite at the site of what is now downtown Jacksonville; this may be the earliest recorded name for that area.