Augustus II, however, did not give up Polish crown and did not abdicate. In May 1704, he formed the anti-Swedish Sandomierz Confederation, called for the levee en masse, and on August 30, signed the Treaty of Narva, establishing the Polish - Russian alliance, and officially declaring war between the Commonwealth and Sweden. This decision resulted in a civil war in Poland - Lithuania, between supporters of Augustus and Leszczyński. Initially, Augustus managed to recapture Warsaw, and win the support of most senators, during a council in Grodno. On February 13, 1706, however, Augustus lost the Battle of Fraustadt, and, facing Swedish occupation of Saxony, gave up his claim to Polish crown in the Treaty of Altranstadt (1706).