The Swedish Empire was dominant in northern Europe around the turn of the 18th century. Peter the Great was seeking to extend Russia’s influence and needed access to Baltic ports to expand trade. Russia formed an alliance with Denmark-Norway and Saxony-Poland and began a combined attack against Sweden in February 1700. Only six months later, a Swedish march on Copenhagen forced Denmark to leave the war upon signing the Peace of Travendal. Poland suffered a number of defeats at Swedish hands and was forced to sign the Treaty of Altranstädt in 1706. Peter realized his position was perilous and offered to return most of the Baltic territory he had acquired. Charles XII of Sweden rejected the offer and turned on Russia but was defeated in the Battle of Poltava in 1709. This marked a turning point in the war as the anti-Swedish alliance re-formed, eventually securing victory in 1721 with a series of treaties that ceded Swedish territory to the alliance.
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