Sir Gilbert de Haydock IV (c.1366 – c.1425) was the 21st great-grandfather of Cometan, classified as one of Cometan’s medieval paternal ancestors in the Taylor family line.
Born in Haydock, Warrington, Lancashire, Sir Gilbert was the husband of Isabel de Houghton and is also known to have been the father of Joan Haydock. Sir Gilbert is recorded as having died sometime before 1425 at Bradley Hall, Eccleston. He was the son of John de Haydock and Joanna de Dutton.
In Cometanic ancestry, Sir Gilbert is categorised as part of the 23rd generation retrograde, and because he was born before 1453, he is classified as a medieval ancestor of Cometan, a title that is rarely bestowed.