King of Wales in the Middle-English Sir Tristrem.
He was attacked by the giant Urgan, who wanted to marry Triamour’s daughter, Blancheflor. Tristan assisted Triamour by slaying the giant, which Triamour rewarded by giving Tristan a dog named Petitcrieu.
He is called Gilan in Gottfried von Strassburg’s version.
Source
Sir Tristrem | c. 1300