Why was st. petersburg founded? to effectively battle the swedish who had previously controlled the land. to provide a port and access to europe. to replace moscow, which had been destroyed in war. to provide a military base for ongoing wars between russia and europe.

To provide a port and access to Europe.

Explanation:

St. Petersburg was founded by Peter the Great during the 17th century. He was interested in having a seaport that was easily accessible from Europe in order to increase trade. Peter captured Nyenskans, which was a Swedish fortress built in this area,  and replaced it with the Peter and Paul Fortress, which became the first building in the new city. The capital was moved from Moscow to Saint Petersburg in 1712.