In the War in Defense of the Constitution, pro-Russian conservative Polish magnates, the Confederation of Targowica, fought against Polish forces supporting the constitution, believing that Russians would help them restore the Golden Liberty. Abandoned by their Prussian allies, Polish pro-constitution forces, faced with Targowica units and the regular Russian army, were defeated. Prussia signed a treaty with Russia, agreeing that Polish reforms would be revoked, and both countries would receive chunks of Commonwealth territory. In 1793, deputies to the Grodno Sejm, last Sejm of the Commonwealth, in the presence of the Russian forces, agreed to Russian territorial demands. In the Second Partition, Russia and Prussia helped themselves to enough land so that only one-third of the 1772 population remained in Poland. Prussia named its newly gained province South Prussia, with Posen (and later Warsaw) as the capital of the new province.