Welby is recorded in the 1086 "Domesday" account as "Wellebi", within two manors in the Threo Hundred of Kesteven. The first manor held 57 households, 7 villeins, 4 smallholders, 37 freemen, a priest, a church, a meadow of , and woodland of . In 1066 Queen Edith was Lord of the Manor, this transferred to William I in 1086, who also became tenant in chief. The second "Domesday" entry shows a manor with 3 villagers, 5 freemen and 4 ploughlands, with a meadow , and woodland of , with the lord in 1066 being Aethelstan, son of Godram. In 1086 the lordship was transferred to Ranulf, with Guy of Craon becoming tenant in chief.