Swedish army crosses the border

The invasion begins

On 21 July 1655 a Swedish army crossed the Commonwealth’s border under Field Marshal Arvid Wittenberg. The Polish Army Museum treats this date as the beginning of the 1655–1660 Polish-Swedish war, known as the Deluge¹.

What followed?

Two days later the Swedes confronted the Greater Poland noble levy near Ujście. The capitulation was signed only on 25 July. These dates show that the surrender at Ujście was not the first moment of the invasion¹².

Why then?

The Commonwealth had faced a Cossack uprising for years and war with Russia since 1654. The Swedish king saw an opportunity for Baltic influence, while the Swedish crown dispute made a settlement harder. Read more in Why did Sweden invade?³⁴.