Followers of this belief system commemorated two founders on the holiday of Eikas on the twentieth day of every month. In Naples, a circle of adherents to this belief system was led by Philodemus of Gadara, a client of Lucius Calpurnius Piso. Gravestones of many members of this movement include the inscription “Non (15[1])fui, fui, (-5[1])non sum.” Every day, followers (15[1])of this belief system recited the (*) tetrapharmakos, (10[1]-5[1])part of its (15[1]-5[1])“principal doctrines.” The founder of this belief system (10[1])is praised for (10[1])defeating the monster Religion in a poem that also discusses the clinamen, or “swerve.” (10[1])For 10 points, name this materialistic (10[1])ancient philosophy (10[2])expounded in Lucretius’ (-5[1])De Rerum Natura, which taught that (10[1])the highest (10[3])good was ataraxia, (10[1])the absence of (10[1])pain. ■END■ (10[1])