In the summer of 1788, having staged a frontier incident as a pretext for declaring war, Gustav III launched an attack on Russia. The success of this venture hinged upon the ability of the Swedish fleet to land a sizeable force within forty kilometres of St Petersburg. A major naval engagement off the island of Suursaari in the Gulf of Finland on 17 July, although indecisive, effectively nullified that part of the plan. Neither the main army nor the Savo brigade achieved their objective of capturing the fortress towns of Hamina and Savonlinna respectively; by early August, both had retired to defensive positions. The mood of discontent and opposition towards the king, which was rife within the officer corps, now burst to the surface, culminating in the formation of a confederation in the army camp at Anjala. This confederation was designed to force the king to make peace and to bring about a new constitutional order in Sweden. The statement issued on 13 August, signed by over a hundred officers headed by the commander of the Finnish army, Major-General Carl Gustav Armfelt, justified the extraordinary action of sending an emissary to the Empress Catherine to sound out the prospects for peace by claiming that Sweden appeared to be the aggressor, in contravention of the constitution which required the consent of the riksdag for an offensive war.