The Westmorland of Apethorpe Archive is of pre-eminent regional, national and international importance. This status is confirmed both by its acceptance in lieu of tax and also by the fact that it is among the 120 estate and family archives that The National Archives considers to be the most significant in the UK.
The Westmorland of Apethorpe Archive spans 700 years and is rich in Elizabethan and Jacobean material. At its core are the state and family papers of Sir Walter Mildmay (1520-1589) one of Elizabeth I's greatest servants. Mildmay was Chancellor of Exchequer the for 30 years and, with Lord Burghley, was in charge of the day-to-day administration of the Elizabethan state. It includes documents signed by Henry VIII and letters and documents signed by Elizabeth I and James I. From later periods, the archive also includes some important Civil War material.
Other highlights include:
- The 1409-10 household accounts of Edward, Duke of York
- Muniments from Thorney Abbey, one of the great Benedictine houses in the Fens
- Lady Grace Mildmay's volumes on the diagnosis and treatment of illness.
- Civil War Papers of Adrian Scrope (1601-1660), Regicide and Governor of Bristol, including letters and papers signed by Cromwell.
- Fine 16th and 17th century illuminated grants-of-arms and pedigrees, commissioned by the Westmorlands to demonstrate their ancient and noble blood.
