Heusden Castle, on the River Maas east of Dordrecht, was built by the Dukes of Brabant in the 14th Century. It became the centre of a township and served as the local munitions store. On 14 June 1680 lightning stuck the tower and ignited 60,000 pounds of gunpowder, largely destroying the castle. A view of the castle, made by Roelant Roghman in 1646-57, now in the Teylers Museum, Haarlem, shows the tower before the explosion (H.W.M. van der Wyck and J.W. Niemeijer, De kasteeltekeningen van Roelant Roghman, Alphen aan den Rijn, 1989-90, I, no. 76).
Valentin Klotz was a military engineer in the service of Stadholder-King William III of Orange, and so would almost certainly have been studying the site with a professional eye. Two drawings of Heusden drawn on the same day as the present view by Josua de Grave, who like Klotz served in the army of the States-General, are in the Rijksprentenkabinet, Amsterdam (K.J. van Hasselt, op. cit., nos. 167-168).
We are grateful to Peter Schatborn for his help in cataloguing this drawing.