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]]
Ptolemy III Euergetes systems. His stone stela is the Canopus Stone of 238 BC. Other well-known examples are the Memphis Stele (Memphis Stone), bearing the Decree of Memphis, about 218 BC, passed by his son, Ptolemy IV, as well as the famous Rosetta Stone erected by Ptolemy Epiphanes, his grandson, in 196 BC. Ptolemy III's stone contains decrees about priestly orders, and is a memorial for his daughter Berenice. But two of its 26 lines of hieroglyphs decree the use of a leap day added to the Egyptian calendar of 365 days, and the associated changes in festivals. He is also credited with