Mayor Thordr of Machecoul (19 March 829-) was the Marshal of Retz from 867 to 869 under Chief Hastein. He came from a lowborn family of pagan Norse Vikings. On 25 September 869, he was replaced as Marshal by Hastein's concubine Ylva af Raumariki, but he was rewarded with the honorary title of Hirdman (brother-in-arms) and a gift of gold.