IV ran from sometime between 1200 and 1400 to around 1700. Most of this period was after European contact began affecting the peoples of Florida. Artifacts recovered from this period include reworked metal of Spanish origin. Occupation continued at Middens A and B on the natural levee along Fisheating Creek, and expanded to new mounds on the prairie away from the stream meander zone. Linear earthworks associated with those mounds also appeared in this period. Maize pollen was found in deposits from this period, after being absent during Period III. Burials from after 1500 were found in the top of Mound B. Most of these burials were flexed (legs bent), while the rest were bundled. Post holes associated with the upper level burials may be from small shelters built over the burials. Burials from Period IV were associated with grave goods, including objects reworked from Spanish gold, silver, copper and brass, unlike those from earlier periods. Some of the grave goods may have been symbols or badges of rank. Fort Center was probably now part of the Calusa realm. Hernando de Escalante Fontaneda, who was held captive by Indians in Florida for 17 years in the 16th century, indicates that the Mayaimi people, who lived around Lake Okeechobee and were therefore the likely inhabitants of Fort Center, were subject to the Calusa. Fontenada describes the Mayaimi as living in very small towns and scattered settlements. Sears states that the Calusa probably did not use Fort Center as a ceremonial center. During Period IV, several living sites were occupied (although not necessarily all at the same time), including Middens A and B, and Mounds 1, 2, 3, 5, 8, and the University of Florida Mound. Most of the mounds were new to this period. Mound 3 was built up from a small natural mound, and had been previously occupied. Mound 8 may be natural. Broken smoking pipes were found at the original ground level under the University of Florida mound, indicating the site may have served a ceremonial purpose before the mound was built. The mounds (not including the middens on the levee) are each big enough for a single house, and each mound is associated with a linear earthwork, which Sears interpreted as "agricultural plots." The linear earthworks varied in size, from 30 to 100 feet wide and 300 to 1,200 feet long. The earthworks were raised two to three