With the issue with the Ottomans now settled, Peter turned his attention back to the north, and to the dismantling of the Swedish Empire on the Baltic. He seized Viborg, Riga, and Reval in 1710. With Charles XII now deposed, the coalition against Sweden was formed again. Peter divided his army between assisting his allies in the south Baltic, and his own attacks in the east. What is now Estonia and Livonia, weakly defended, fell quickly. Peter then moved north and invaded Finland in 1713. Meanwhile, Charles, traveling incognito, returned to Sweden in 1714. The Swedes, with their empire broken and nothing left to lose, continued to fight. At sea, the prebuilt Russian fleet, which had proved useless when victory was still uncertain, was proving its worth at consolidating Russian victories; victories at Gangut in 1714, Ösel in 1719, and Grengam in 1720 gave Peter control of the sea.