[The Norman baron] Todeni began building the first Castle here in 1067. It was built to a typically Norman motte-and-bailey design. With a timber framed fortress in an enclosed courtyard, it took full advantage of the site’s defensive position high up on the ridge. Todeni also founded a priory at the foot of the Castle, where he was buried on his death in 1088. By 1464, the Wars of the Roses had taken their toll on the first castle, and it was more or less in ruins.
Belvoir rose again some 60 years later with the construction of the second Castle to a medieval design for Sir Thomas Manners. . . . The second Castle was a much nobler structure with a central courtyard, parts of which can still be recognized today. In 1649, the second Castle was destroyed by Parliamentarians after Royalists had seized it during the Civil War (1642-1651).
The third Castle, completed in 1668 to a design by John Webb – a pupil of Inigo Jones – was created for John the 8th Earl under the instruction of his wife, Frances the Countess. She insisted on rebuilding it as a palatial country house without any resemblance to a castle.
In 1799, the 5th Duke of Rutland married Lady Elizabeth Howard. The new Duchess of Rutland soon chose architect James Wyatt to rebuild the castle in the romantic Gothic Revival style. The Duke, one of the wealthiest landholders in the United Kingdom of Great Britain and Ireland, sold seven assorted villages and their surrounding lands to fund the massive project. The project was nearing completion when, on 26 October 1816, it was almost destroyed by a fire. . . . Rebuilt, again, to largely the same designs, at a cost of an additional £82,000 (£7.79 million today), the castle was largely completed by 1832. The architect Sir James Thornton (who was the Duke’s friend and chaplain and Vicar of nearby Bottesford) was chiefly responsible for this rebuilding, and the result bears a superficial resemblance to a medieval castle.
There are still some remains of the original large round Norman keep, and up to the commencement of the present century a good deal of the ancient work existed ; but about the year 1800 the then Duke of Rutland, with the aid of the architect Wyatt, proceeded to build Belvoir Castle anew, in a modern Gothic style, when most of the structure that was old, and should have been religiously preserved, was removed and perished.
“The Castles of England: their story and structure, Vol 1”, James Mackenzie, 1897, pp. 411-2