Ptolemy I Soter rivals after Alexander's death. For example, Arrian's account of the fall of Thebes in 335 BC ("Anabasis" , a rare section of narrative explicitly attributed to Ptolemy by Arrian) shows several significant variations from the parallel account preserved in Diodorus Siculus (17.11–12), most notably in attributing a distinctly unheroic role in proceedings to Perdiccas. More recently, J. Roisman has argued that the case for Ptolemy's blackening of Perdiccas and others has been much exaggerated. Ptolemy personally sponsored the great mathematician Euclid. He found Euclid's seminal work, the "Elements", too difficult to study, so he asked if there were an easier
Ptolemy II of Telmessos a paternal first cousin called Antipater Epigonos and likely he had a paternal second cousin called Epigonos. Through his father, Ptolemy II was a direct descendant of Lysimachus who was one of the Diadochi of the Greek King Alexander the Great who was King of Thrace, Asia Minor and Macedonia and Ptolemy I Soter another of the Diadochi of the Greek King Alexander the Great who was the founder of the Ptolemaic dynasty of Ancient Egypt and his wife, Berenice I of Egypt. Berenice I was the great-niece of the powerful Regent Antipater, through her maternal grandfather Cassander, the brother