Ehrensvärd was a field marshal and the designer of the Sveaborg fortress outside Helsinki. He drew up plans for the fortress in 1747, and construction began the following year. Sveaborg became the realm’s main bastion facing east. Ehrensvärd grew up surrounded by art at Fullerö Castle outside Västerås, and was drawing and painting at an early age. He saw Joseph Vernet’s art on a journey to Paris, and its scenic expression influenced him.