six years (1966–1971) by teams from the University of Florida, Colgate University and Florida Atlantic University. The State of Florida acquired the Fort Center site from Lykes Brothers in 1999 as part of the Fisheating Creek Ecosystem. It is operated as a wildlife management area. In 2010 further research at the Fort Center site was conducted by Victor D. Thompson and Thomas J. Pluckhahn with grants from the National Geographic Society, Ohio State University and the University of South Florida. their work confirmed much of Sears' data but differed significantly on the function and archaeological significance of the Fort Center ritual place. Thompson and Pluckhahn are the first archaeologists to view Fort Center as one of many persistent Monumental ritual earthworks in the Glades/Calusa cultural region of south Florida. They concluded that the area is one of the most important hunter-gatherer intensive earthworks groups in world prehistory. Origins Sears believed that the freshwater regions of peninsular Florida were peopled by immigrants from northern South America who preceded Arawakan language-speakers through the Antilles. He cited the use of celts and adzes made from conch-shells, the proposed derivation of the Timucuan language from South American roots, the cultivation of maize, and the use of earthworks to form fields in savannahs (wet prairies) as was done in South America. He also cited the use of fiber-tempered pottery, similar to that used in South American, and distinct from pottery used in the rest of eastern North America. Sears divided the period of occupation at Fort Center into four periods. Period I began before 450 BCE, perhaps as early as 1000 BCE, and lasted until around 200 CE. Period II ran from about 200 to between 600 and 800, followed by period III until 1200 to 1400, and then period IV up to about 1700. Archaeologists have been skeptical of Sears' migration theory because there is no evidence of South American root crops being introduced to Florida, and the evidence from pottery does not give a clear south to north sequence of introduction within Florida. There is some support for the idea that maize, and at least one strain of tobacco, were introduced into Florida by a sea route. Other archaeologists have noted that the peoples living in the Greater Antilles prior to the arrival of Arawakan-speakers were hunter-gatherers, not agriculturists. They believe that the agricultural Arawakan-speaking Tainos did not reach Hispaniola and Cuba until