Prior to 600 AD, the lake Mälaren was connected to the sea, but due to land elevation, the lake was slowly cut off and boats had to be ported over land to and from the lake.
The lake Mälaren was connected to the sea, but due to land elevation. This was prior to 600 AD. The lake was slowly cut off. This was prior to 600 AD. Boats had to be ported over land to and from the lake. This was prior to 600 AD.