Pausanias Description of Greece 1.10.4

[4] Since Lysimachus, then, overlooked Arsinoe 's murder of Agathocles, Lysandra fled to Seleucus, taking with her her children and her brothers, who were taking refuge with Ptolemy and finally adopted this course. They were accompanied on their flight to Seleucus by Alexander who was the son of Lysimachus by an Odrysian woman. So they going up to Babylon entreated Seleucus to make war on Lysimachus. And at the same time Philetaerus, to whom the property of Lysimachus had been entrusted, aggrieved at the death of Agathocles and suspicious of the treatment he would receive at the hands of Arsinoe , seized Pergamus on the Caicus , and sending a herald offered both the property and himself to Seleucus.

[4] Since Lysimakhos, then, entrusted to Arsinoe the murder of Agathokles, Lysandra fled to Seleukos, taking along her children and her brothers, who were taking refuge with Ptolemy and who finally adopted this course. They were accompanied on their escape to Seleukos by Alexander, who was the son of Lysimakhos by an Odrysian woman. So, going up to Babylon, they entreated Seleukos to make war on Lysimakhos. And, at the same time, Philetairos, to whom the property of Lysimakhos had been entrusted, aggrieved at the death of Agathokles and suspicious of the treatment he would receive at the hands of Arsinoe, seized Pergamon-on-the-Kaïkos, and sending a herald offered both the property and himself to Seleukos.