Gereint V was the Prince of Kemr from 864 CE to 871 CE. He was one of the younger sons of Gereint IV and succeeded upon the sudden death of his older brother Llewfelen II. He had been raised at least part of the time in England and his wife, Elanor of Kent, was English.
He is perhaps most famous as subject and title character of the Gwilim Trammelpila] play of the same name. The play itself is full of anachronisms, some of which have become popularly held as gospel in the common imagination.
The truth is that he was praised in his lifetime as a a handsome and charming prince who married for love. It was held by many that his older friend Pedr of Rheged was all but the power-behind-the-throne. It is known that Gereint's younger brother Emreis led a rebellion against him, during which both were killed in battle, although the details are few. Some accounts of the time held that Gereint lingered for weeks after receiving a fatal wound, while others claimed Emreis was captured and subsequently murdered/executed.
He was succeeded by his son Aleisandr II.
Many songs and stories grew up around the dashing Gereint and his death in battle, many of them either contradictory (his dying young yet living to be a hundred, for example) or known to be wrong (such as his conquest of England and Scotland). His ghost was said to have impregnated girls who slept on his (supposed) grave. Legend had it he tricked the Angel of Death into a leather sack, only agreeing to let him go if he allowed the royal line of Kemr to remain unbroken. One song claimed he turned into a dragon to seduce a female of the species to leave Kemr forever and give him her treasure to boot. In the middle ages, many considered Gereint to be the patron saint of chivalry.
In the 1960s there was a popular cartoon series in the Federated Kingdoms called simply The Adventures of Prince Gereint about the future monarch as a boy and his wild adventures with a talking cat who had once been a wizard. It was very popular and ran for four years. Released onto Video Disk the series has been a bestseller.