Brown's sketches hardly ever appear at auction, most remaining in the private collections of those who commissioned them. This rare example shows the view north-east across the lake from Blenheim Palace towards the town of Woodstock. Its purpose was to show the effect of Brown's proposal to Gothicise the existing perimeter wall – much as a CGI image might be used by an architect today to illustrate a design to a client.
The sketch is in pen, grey ink and watercolour on laid paper. It is detailed and appears to be accurate – a very similar view can be experienced by visitors to the grounds of the Palace today though this particular scheme was never realised. The main buildings are inscribed with letters and identified in a key at the bottom left of the sketch.
Brown was brought to Blenheim Palace in 1764 by the 4th Duke of Marlborough to develop the gardens, creating what has been described as the quintessential English stately home garden.
He naturalised the landscape of the 2,000 acres, planting trees and installing man-made undulations to soften the contours. His most enduring and famous change, however, was the creation of the great lake which appears in the foreground of the sketch. He dammed the River Glyme and flooded the lower storeys of Vanburgh's incongruously enormous bridge, said to hold 30 rooms, and in the process brought it into proportion with the house and the rest of the gardens.
Brown's sketch remained in the Marlborough family until the 10th Duke made a gift of it to the town of Woodstock in the 1930s. It is estimated to be worth between £70,000 and £100,000.