Safety Harbor mounds generally built on late Weeden Island period mounds. Changes in decorated ceramics and the presence of European artifacts support a division of the Safety Harbor culture into four phases. Pre-contact phases were the Englewood, 900-1100 and the Pinellas, 1100-1500. Phases during the Spanish colonial period included Tatham, 1500-1567, and Bayview, 1567-1725. The Safety Harbor culture is defined by the presence of burial mounds with ceramics decorated with a distinctive set of designs and symbols. Ceramics found elsewhere at Safety Harbor sites (in middens and village living areas) are almost always undecorated. Major Safety Harbor sites had platform, or temple, mounds. The term "temple mound" is based on the description by members of the de Soto expedition of a temple on a constructed earthwork mound in a Safety Harbor village. Bullen and Milanich state that the temples were likely charnel houses, where bodies were prepared and stored for later burial. Several of the temple mounds have been destroyed since the 19th century, but at least fifteen have been documented as having once existed around Tampa Bay and on the Gulf coast near Tampa Bay. These temple mounds were rectangular and had flat tops, usually with a ramp leading up to the top on one side. Known Safety Harbor sites with "temple" mounds include:  Possible Safety Harbor temple mound sites include:  Three platform mounds east and south of Charlotte Harbor, the Acline Mound (Aqui Esta site, near Punta Gorda), Howard Shell Mound (Bokeelia Island, at the north end of Pine Island), and Brown's Mound (Pineland site, near Pineland on Pine Island), differ from Safety Harbor temple mounds in having a "U"-shaped platform, and no ramps. This difference in form may indicate the mounds belong to the Caloosahatchee culture instead of the Safety Harbor culture. Luer and Almy also note that the large Bostic Temple Mound in Hardee County, which is associated with a village area and burial mounds, was contemporary with Safety Harbor temple mounds. They suggest that this site was the center for a distinct cultural and political system oriented to the Peace River valley. There are two "truncated rectangular" mounds at the Crystal River site that have mentioned as possible Safety Harbor temple mounds, but the other mounds there pre-date Safety Harbor, and there is little evidence of Safety Harbor use of the site.