Thonock Castle Hills

Also known as, or recorded in historical documents as; Gainsborough

In the civil parish of Thonock.
In the historic county of Lincolnshire (Modern Authority of Lincolnshire, 1974 county of Lincolnshire).

Ringwork and baileys. It is thought to date from the late C11 or mid C12. The monument takes the form of a ringwork with banked and ditched baileys adjoining it to the north and south. The central area of the ringwork is roughly circular in plan, measuring 20m in diameter, and includes a hollow thought to represent the location of buried building remains such as a hall. The central area is enclosed by a bank and external ditch. The bank measures up to 10m in width. The ditch is steep-sided, measuring 15m in width. The northern side of the ringwork is enclosed by a bailey and believed to be contemporary with the ringwork. The bailey is semi-circular in plan, the enclosed area measuring 80m, and is surrounded by a ditch with an internal bank. The southern bailey adjoins the south and east sides of the ringwork and is thought to represent a subsequent phase of defensive work. Supposedly retrospectively licensed to crenellate in 1142, but actually a royal confirmation of Earl William of Lincoln possession of the castle.

This site has been described as a;
Timber Castle.
The confidence that this site is a medieval fortification or palace is Certain.
Cropmarks/slight earthworks remains.

A supposed Royal licence to crenellate was granted in 1142.

This site is a scheduled monument protected by law.

The Ordnance Survey Map Grid Reference is SK81849151

Modern Map from Good for landscape form and features	Modern Map from Good for general location
Air Photo from	1st edition OS Map from

Sources of information, references and further reading

PastScape number; 325070

• Web site links
  • http://www.castleuk.net/castle_lists_north/112/gainsboroughcastle.htm
• Books
  • Salter, Mike, 2002, The Castles of the East Midlands (Malvern) p49
    Pettifer, A., 1995, English Castles, A guide by counties (Woodbridge) p148 [slight]
    Roffe, David, 1993, 'Castles' in Bennett, S. and Bennett, N. (eds), An Historical Atlas of Lincolnshire (University of Hull Press) p40-1
    King, D.J.C., 1983, Castellarium Anglicanum (London: Kraus) Vol1 p260
    Renn, D.F., 1973 (2edn), Norman Castles of Britain (John Baker)
    Sir Francis Hill, 1965, Medieval Lincoln p180
    Round, J.H., 1892, Geoffrey de Mandeville (Oxford) p144
• Journal Articles
  • King, D.J.C. and Alcock, L., 1969, 'Ringworks in England and Wales' Château Gaillard Vol3 p90-127
    Vickers, S.B., 1936-8, Lincolnshire Magazine Vol3 p155-9
    [Clark?], 1881, The Builder Vol41 p662
• Primary (Medieval documents or transcriptions of such documents - This section is far from complete and the secondary sources should be consulted for full references.)
  • Great Coucher, ii, fol. 445
• Antiquarian (Histories and accounts from late medieval and early modern writers)
  • Chandler, John, 1993, John Leland's Itinerary: travels in Tudor England (Sutton Publishing) p295
    Toulmin-Smith, Lucy (ed), 1910, The itinerary of John Leland in or about the years 1535-1543 (Bell and Sons; London) p33