...the Swedes had begun laying siege to…
August 1605 CE
...the Swedes had begun laying siege to Riga.
Their main mission is to capture this important city, one of the largest Baltic ports.
Chodkiewicz moves in to relieve the garrison at Riga, but finds that the Swedes are also sending in reinforcements under Lennartson.
Chodkiewicz moves in on Lennartson; however, he decides not to allow for open battle and retreats into a fortress.
On finding out that Charles himself is now marching in with yet more reinforcements (around five thousand), Lennartson decides to link up with the king and assault Riga together.