Apollodorus Library 3.11.2

[2]
  Of the sons born to Leda Castor practised the art of war, and Pollux the art of boxing; ¹ and on account of their manliness they were both called Dioscuri. ² And wishing to marry the daughters of Leucippus, they carried them off from Messene and wedded them; ³ and Pollux had Mnesileus by Phoebe, and Castor had Anogon by Hilaira. And having driven booty of cattle from Arcadia, in company with Idas and Lynceus, sons of Aphareus, they allowed Idas to divide the spoil. He cut a cow in four and said that one half of the booty should be his who ate his share first, and that the rest should be his who ate his share second. And before they knew where they were, Idas had swallowed his own share first and likewise his brother's, and with him had driven off the captured cattle to Messene. But the Dioscuri marched against Messene, and drove away that cattle and much else besides. And they lay in wait for Idas and Lynceus. But Lynceus spied Castor and discovered him to Idas, who killed him. Pollux chased them and slew Lynceus by throwing his spear, but in pursuing Lynceus he was wounded in the head with a stone thrown by him, and fell down in a swoon. And Zeus smote Idas with a thunderbolt, but Pollux he carried up to heaven. Nevertheless, as Pollux refused to accept immortality while his brother Castor was dead, Zeus permitted them both to be every other day among the gods and among mortals. ⁴ And when the Dioscuri were translated to the gods, Tyndareus sent for Menelaus to Sparta and handed over the kingdom to him.