The above was painted by Anton Wilhelm Tischbein (1730-1804) in 1783. The scene depicts the grounds of the spa - the ruined castle, the kitchen and the carousel in the background. In the foreground (right) is the hereditary prince William IX of Hesse-Kassel (1743-1821) with six year-old son William. William IX, at the time, was the ruler of the principality of Hanau, subsequently becoming William IX, Landgrave of Hesse-Kassel - after his father Frederick II, Landgrave of Hesse-Kassel had died in 1785 - and then William I, Elector of Hesse.
The Hanau-Wilhelmsbad spa, fashionable from 1777 to 1785, was the location of the Masonic Congress in the summer of 1782 (16 July - 29 August). William IX made it his summer retreat, and the ruined castle, prominent in the painting, was where high-degree Masons from the whole of Europe had deliberated the fate of the rite of Strict Observance.