Vidumavi or Galadwen (TA pre-1255-TA 1332) was the daughter of the King of Rhovanion Vidugavia and the wife of 20th King of Gondor Valacar.
Two years after her father helped the Regent of Gondor Minalcar in his war against the Easterlings, Minalcar sent Valacar to live with them and learn about their traditions as an ambassador.
Shortly after Vidumavi and Valacar were married and in TA 1255 she gave birth to a son called Eldacar.
In TA 1260 Valacar was recalled to Gondor to take the first steps in running the Kingdom. Vidumavi arrived with him and was given the Sindarin translation of her name, which was Galadwen.
Although living to be some point over 77, a good age for her people, it was a far shorter lifespan to that of the Dunedain.
She never saw her husband take the throne.
Trivia– Christopher Tolkien believes her name to be a Latinised spelling of the Gothic name Widumawi meaning “Wood-Maiden”