lness they are not
very prominent, and it is doubtful whether they would ever have become
famous, except for one of those little accidents which make the fortunes
of gods as well as of men. It so happened that horses began to be used
in warfare more than for the mere drawing of chariots; a primitive sort
of cavalry came into being, produced by mounting heavy-armed
foot-soldiers on horseback. With this cavalry the "Twin-Brothers"
(_Dios-kouroi_ = "Sons of Zeus"), especially Castor, became prominent.
Just as the Greek merchants had taken Herakles with them when they set
out to plant colonies in Southern Italy, so the heavy-mounted horsemen
carried their god Castor with them wherever they went. The Italic tribes
in their turn were quick to seize upon this idea of cavalry, and with
it as an essential part went its divine patron, Castor. Thus the
Castor-cult moved steadily northward, carried, as it were, on horseback.
At last it reached Latium, and there the little town of Tusculum,
afterwards so famous as the residence of Cicero, became in some
unaccountable way an important cult-centre, and did for Castor what
Tibur had done for Hercules, _i.e._ latinised him, so that Rome received
him not as an alien but as one of her kin. There can be little doubt
that the Roman cult actually did come from Tusculum, and that in its
introduction into Rome, as in every other step on its march, it was
connected with the reorganisation of the cavalry. This would seem to
imply that Tusculum was famous for its cavalry and that Rome took the
idea of it from her--statements for which we have unfortunately no other
confirmation, though we have abundant proof of the cult at Tusculum and
of Rome's close association with it.

Castor was thus the patron of the "horsemen" (_equites_) and his great
day was July 15, when the horsemen's parade took place. Possibly this
had been the date of the festival at Tusculum, a day especially
appropriate because it was the Ides of the month, and the Ides were
sacred to Juppiter, whose sons Castor and Pollux (_Dios-kouroi_) were
supposed to be. It is extremely interesting in the light of this
knowledge of the true state of affairs to see how legend later
explained the coming of Castor and Pollux. It was an incident in the
mythical war which was supposed to have taken place after the last
Tarquin had been driven out, and the republic had been started. The
adversaries of Rome, allied with Tarquin, notably Octavius Mam