Branwen

Branwen : She marries the King of Ireland, Matholwch but the marriage does not turn out well. Her husband treats her badly. She tames a starling and sends it with a message to her brother, Brân and he brings a force from Wales to Ireland to rescue her resulting in a war between the Irish and the Welsh. They eventually sail home to Wales. Upon reaching Wales, they realise that Bran has been hit by a poisoned arrow to his leg, and he dies. Branwen, overwhelmed with grief for everyone she has lost, dies of a broken heart. Her grave is said to be at Llanddeusant on Anglesey on the banks of the river Alaw. You can read the story here https://en.wikipedia.org/wiki/Branwen