He was unmarried and wanted his wealth from his estate across Lincolnshire to create a school in his name.

The buildings were opened around 1680, and the Upper School Library dates from this time.

New buildings were added in 1879, and the Nelthorpe family have retained strong links with the school.

[1] The school took part in a Great War research project supported by the Heritage Lottery Fund.

Since 1996, it has had a partnership with the Gymnasium Leoninum [de] in Handrup, Lower Saxony (Niedersachsen) in Germany.