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 Keraunos Corupedium in 281 BC against Seleucus, Ptolemy Keraunos murdered Seleucus in order to gain control over the territories of his former protector. He then rushed to Lysimachia where he had himself acclaimed king by the Macedonian army. At this time he also formally relinquished his claim to the Egyptian throne. To secure his position on the throne, Ptolemy asked his half-sister Arsinoe, the widow of Lysimachus, to marry him. Later in the year, he made an alliance with Pyrrhus of Epirus. His only rival, Antigonos Gonatas, son of the ex-king of Macedon, Demetrius I Poliorcetes, was confined in the city