For 10 points, give the shared name of this line of pharaohs, the last three of which ruled jointly with Cleopatra.
The second one, known as Philadelphus, divorced his wife Arsinöe I to marry his sister Arsinöe II. The first one was the son of Lagus and received the name Soter. That founder had served as a general under Alexander the Great. For 10 points, give the shared name of this line of pharaohs, the last three of which ruled jointly with Cleopatra.
The second one, known as Philadelphus, divorced his wife Arsinöe I to marry his sister Arsinöe II.
{Ptolemy} [or {Ptolemaic dynasty} or other equivalents]