Ptolemy or optical factors and those caused by judgmental factors. He offered an obscure explanation of the sun or moon illusion (the enlarged apparent size on the horizon) based on the difficulty of looking upwards. There are several characters or items named after Ptolemy, including: [[File:Ptolemaeus - Quadripartitum, 1622 - 4658973.tif|thumb|"Quadripartitum", 1622]] [[Category:Ptolemy| ]] [[Category:100 births]] [[Category:170 deaths]] [[Category:1st-century Romans]] [[Category:2nd-century Romans]] [[Category:2nd-century philosophers]] [[Category:2nd-century poets]] [[Category:Egyptian calendar]] [[Category:Ancient Greek astrologers]] [[Category:Ancient Greek astronomers]] [[Category:Ancient Greek mathematicians]] [[Category:Ancient Greek music theorists]] [[Category:Astrological writers]] [[Category:Claudii]] [[Category:Egyptian astronomers]] [[Category:Egyptian mathematicians]] [[Category:Epigrammatists of the Greek Anthology]] [[Category:2nd-century people of Roman Egypt]] [[Category:Ancient Greek geographers]]
Egyptian calendar the Macedonian Ptolemaic Dynasty came to power in Egypt, continuing to use its native calendars with Hellenized names. In 238 , Ptolemy III's Canopus Decree ordered that every 4th year should incorporate a sixth day its intercalary month, honoring him and his wife as gods equivalent to the children of Nut. The reform was resisted by the Egyptian priests and people and was abandoned. Egyptian scholars were involved with the establishment of Julius Caesar's reform of the Roman calendar, although the Roman priests initially misapplied its formula and—by counting inclusively—added leap days every three years instead of every four. The