The Riga garrison consisted of 300[4][2][6][7]–400[3] foot soldiers and 3,700[8][7]–7,000[2][4] burgher militia, although the entire population of 30,000 supported the defense.

[2][4] When Gustavus Adolphus personally inspected the defences of Riga on 21 August, the Swedish army there consisted of 15,350 infantry, 2,500 cavalry, and 56 cannons.

Thousands of Swedes were working on digging tunnels under the walls of the city to be able to destroy important parts of the defensive structures.

While the Swedes placed straw in their hats, so they could distinguish themselves from the defenders, Gustavus Adolphus was persuaded by his entourage to give the city one last chance.

They explained that the Swedish king could not take responsibility for the amounts of blood that would flow if the Swedes were forced to storm the city, and as a result, Riga received a period of 6 hours to deliberate whether or not to surrender.

[13][11] The Swedish conquest of Riga sent shockwaves through Europe, as it was the first time a Protestant leader defeated a Catholic great power.

[13][11] Following the conquest, Gustavus slowly occupied most of Livonia, and by the end of the year, he crossed the Daugava and moved his army into Courland, where he took the capital of Mitau in October.