Original: It is believed to be a copy of a painting described by Pliny the Elder (XXXV, 110) which had been painted by Philoxenus of Eretria for King Cassander of Macedon at the end of the 4th century BC, or even of a painting by Apelles contemporaneous with Alexander himself.
Simplified: It is believed to be a copy of a work described by Pliny the Elder (XXXV, 110) which had been painted by Philoxenus of Eretria for King Cassander of Macedon at the end of the 4th century BC.