[3] The identity of the original architect of Cromwell House remains unknown, but it is certainly a tour-de-force on the part of a highly skilled brick-layer/contractor.

It is recognised as one of the finest examples, along with Kew Palace, of the 17th-century "artisan mannerist" style of domestic architecture in London to have survived virtually intact.

Sir Richard commissioned wooden carvings of military figures of the Stuart period to stand on each newel post[3] of the staircase; and in 1639, when he obtained his grant of arms, he had them incorporated into the centre of the elaborate plaster ceiling of the principal room.

[3] During its period as a school in the mid-19th century, a gabled rear extension was added for use as a dining hall, and in 1865 a serious fire destroyed the roof, the old dome, and the second floor.

[1] Sadly, while the house stood empty in the 1980s a number of architectural antiques were stolen from it, including most of the important carved wooden figures lining the staircase and a marble chimneypiece in an upstairs room.

John Ireton, a brother of the General, was a leading resident of Highgate and was a friend of the Sprignells, and one of them married a daughter of one of those who signed the death warrant of Charles II.

[3] Escaping the inquisition, Alvares (or Alvaro), a wealthy merchant of Portuguese Jewish origins, had arrived in England in 1661 as part of the entourage of Charles II's wife, Catherine of Braganza.

The building became the suburban hub of the large da Costa clan, and during their 74-year ownership the house was expanded to meet their needs.

[9] In 1705, Alvares da Costa bought back the nineteen acres of adjoining land sold by Sir Robert Sprignell, eighteen acres (7.2 hectares) of which was subsequently sold in 1742 by his son who had inherited the estate, but had been in financial difficulties ever since losing heavily in the South Sea Bubble of 1720.

[4] From 1834, Cromwell House was used as a boys' school, run first by William Addison, then from 1843 by Gerrit Van der Linde (1808–1858), a Dutch poet and scholar, who ran a college français, and after his death in 1858 by the Rev.

[10] The Hospital moved out of the building in 1924, and the remainder of the lease was bought by the Mothercraft Training Society, founded by Dr Truby King, who espoused a strict method of infant care and nutrition.

[3] Between 1928 and 1930 the Society built a residential annex, called The Princess Elizabeth of York Hostel,[11] on the remaining acre of land originally acquired by Alvares da Costa in 1705, and in 1939 the buildings became the Truby King Home for Children.

In 1951 the Mothercraft Training Society closed and The Princess Elizabeth of York Hostel (now listed Grade II) was sold separately to the Metropolitan Police Service as accommodation for police officers, and is now student accommodation, accessed from Winchester Place, called Princess Elizabeth House.