Rider's True Name is Europa (エウロペ, Eurōpē?), a Greek Princess of the kingdom of Phoenicia and one of the God Zeus' many mortal concubines in ancient Greek Myth, in her legend Zeus the king of the Olympian gods,infamous for his dalliances with Mortal Women,Goddesses and Nymphs, took notice of her immense beauty and thus then decided to add her to his many conquests. In order to have her for himself without his wife Hera noticing, Zeus transformed himself into the form of a pure white bull in order coax her into riding him and once she did, he immediately ran into the sea and would eventually bring her to the island of Crete, where he then revealed his true identity and crowned her Crete's first Queen and together the couple had three sons: Minos, Rhadamanthus, and Sarpedon.
Her eldest son Minos in particular would eventually rise and become the king of Crete and marry Pasiphaë, a daughter of the Sun Titan Helios and sister to King Aeëtes of Colchis and the Witch Circe and through her eldest son's heretical actions against the God Poseidon eventually become the step-father to the Minotauros and thus her step-Grandson.
The general direction of the sea and the supposed land mass there that Zeus carried her off too, eventually became known as Europe by the Phoeniciaian people in honor for their abducted princess and in time this became the continent's official name.