The new constitution of August 20, 1772 which Gustav III imposed upon the Riksdag of the Estates, converted a weak and disunited republic into a strong but limited monarchy. The estates could assemble only when summoned by him; he could dismiss them whenever he thought fit; and their deliberations were to be confined exclusively to the propositions which he laid before them. But these extensive powers were subjected to important checks. Thus, without the previous consent of the estates, no new law could be imposed, no old law abolished, no offensive war undertaken, no extraordinary war subsidy levied. The estates alone could tax themselves; they had the absolute control of the Riksbank - the Bank of Sweden, and the right of controlling the national expenditure.