Shortly after the conquest, the lordship of Tattershall, together with the hamlet of Tattershall Thorpe, and several other estates, was given by King William to Eudo and Pinso, two Norman nobles, who had attended him into England, but who, though sworn brothers in war, were not otherwise related. On the division of the estates between these chieftains, this manor became the property of Eudo, who fixed his residence here. Upon his death his estates descended to his son, Hugh Fitz Eudo, who, in the year 1139, founded an abbey for Cistertian monks at the neighbouring village of Kirkstead. Hugh was succeeded by his son Robert, who left issue a son named Philip. Philip, after serving the office of sheriff of Berkshire in the seventh year of the reign of Richard the second, and also of Lincolnshire in the eighth, ninth and tenth years of the same king, was succeeded by his son Robert, the second of that name, who, in the year 1201, procured from King John, by means of a present of a well-trained goshawk, a grant to hold a weekly market on Thursday, on this manor. Robert was followed by his son of the same name, who about the year 1230, obtained from Henry the third a licence to build a castle at this place, together with a grant of free warren in all his demesne lands. The male line of Eudo was continued in regular descent, by Robert the fourth, fifth, sixth, and seventh; upon the death of the latter of whom in his minority, it became extinct, and the inheritance was divided between his three sisters. Tattershall became the portion of Joan, one of the co-heiresses, who married Sir Robert Driby, and who had issue by him a daughter and heiress Alice, afterwards married to Sir William Bernack. John, the son of this latter marriage, was succeeded by William, who died a minor, and left his sister Maud his heiress. The Fitz Eudos, from the place, assumed the cognomen of Tateshall, and by that title had summons to parliament among the great barons of the realm. Maud, the heiress of the Bernack family, married Sir Ralph, afterwards Lord Cromwell, who, in her right, became lord of this manor; and upon his death, which happened on the twenty-seventh day of August in the year 1398, left his son Ralph his heir, who died in 1416, and was succeeded by a son of the same name. In the year 1433, this latter Ralph was by Henry the sixth appointed Treasurer of the Exchequer. He died without issue on the fourth of January, 1455; whereby his two nieces, the daughters of his sister, the wife of Sir Richard Stanhope, became his co-heiresses.