Anseau de Cayeux or Anselm de Cayeux (Greek: Ασέλ δε Kάε) was a French knight from Picardy, who participated in the Fourth Crusade (1202-1204) and later became one of the leading nobles of the Latin Empire, serving as regent in Constantinople (1237-1238). He was married to Byzantine princess Eudokia Laskarina, younger daughter of former emperor Theodore I Laskaris.[1][2]