Since 150 000 years ago an Iceage began, achieving the glacial maximum in Europe by about 20 000 years ago. A several thousand meters thick icesheet covered Scandinavia and Central Europe. Global waterlevels were 120 meters below today´s sea level.
The Baltic Ice Lake around 12,600-10,300 BC gradually formed in the Baltic Sea basin as glaciation retreated from that region at the end of the Pleistocene. The post-glacial Yoldia Sea was immediately subsequent to the Baltic Ice Lake.
Yoldia Sea prevailed 10,300 – 9500 BC after the Baltic Ice lake, was drained to sea level during the Weichsel glaciation. The sea ended gradually when isostatic rise of Scandinavia closed or nearly closed its effluents, altering the balance between saline and fresh water. The Yoldia Sea became Ancylus Lake.
Ancylus Lake existed in northern Europe approximately from 9500 to 8000 years BC, being in effect one of various predecessors to the modern Baltic Sea.