What is "lagus"

Lagus ( Greek Λάγος; lived 4th century BC) from Eordaea was the father, or reputed father, of Ptolemy, the founder of the Ptolemaic dynasty. He married Arsinoe, a concubine of Philip II, king of Macedon, who was said to have been pregnant at the time of their marriage, on which account it is told that the Macedonians generally looked upon Ptolemy as in reality the son of Philip; but it is possible that this is a later myth fabricated to glorify the Ptolemaic dynasty. From an anecdote recorded by Plutarch, it is clear that Lagus was a man of obscure birth; hence, when Theocritus calls Ptolemy a descendant of Heracles, he probably means to represent him as the son of Philip. Lagus is believed by some to have subsequently married Antigone, niece of Antipater, by whom he became the father of Berenice, afterwards the wife of Ptolemy, but this is based on a misreading of a corrupt scholium; her father's name was almost certainly Magas.