When Zeus attempted to copulate with Aphrodite on the island of Cyprus, Aphrodite escaped his advances and Zeus's seed was spilt on earth. Earth, being synonymous with the titaness Gaia, received the seed and thus were Cyprian centaurs born.
Cyprian centaurs were not related to the more traditional centaurs of Thessalia. Main difference was their bull-like horns. They may also have been less savage than their Thessalian counterparts, as they were representing fertility rather than virility.
They, however, were not completely devoid of their bestial nature, as Dionysus had no trouble in recruiting Cyprian centaurs as part of his army when he had been commanded to assault India by Zeus.