The Baltic Sea lies largely outside the history books before the High Middle Ages.

The legions of the ancient Romans never reached there. Their main interest in the region was the acquisition of amber, fossilised tree resin which washes up on the Baltic coastline, and has been prized for its colour and natural beauty since Neolithic times.

In the early Middle Ages, the Baltic was still an area of which little was known by the

literate societies of the Franks, the Italians or the Byzantines.

Protected by thick forests, swamps and inhospitable weather, its main significance was as part

of an important trade route that developed between Scandinavia, the lands of Kievanruz,

and Constantinople.

Only from the 12th century did the outside world start to encroach on the lives of the local people.

There are various neighbours with newfound confidence after recovering from the age of the Vikings,

and the conviction of their Christian religion were keen to expand into this last untamed corner of Europe.

The 12th to 14th centuries in particular were to be tumultuous times that would decide the fate of the peoples of southern and eastern Baltic.

This set of episodes covers the period from approximately 1,100 to 1242, up to the Battle of Lake Papus,

also known as the Battle of the Ice, 1242, between the so-called Northern Crusaders who fought for the Roman Church and an army of Orthodox Russians.

Welcome to a history of Europe, key battles, the Battle of Lake Papus, the year 12, 42, part one of five.

The Baltic Sea is an extension of the Atlantic Ocean into Northern Europe,

surrounded by the modern nations of, if you go clockwise, Denmark, Sweden,

Finland, Russia, Estonia, Latvia, Lithuania, Poland and Germany.

Thousands of years ago, though it was a great lake, known to geologists as Lake and Silas,

formed by melting glaciers at around

6,600 BC at the end of the last Ice Age. Lake and Silas was surrounded by extensive marshland

and fed by rivers from Central Europe and the Scandinavian Highlands. In about 4,500 BC, its waters began seeping through southern Scandinavia and started mingling with the North Sea.

One channel became the Ullusand, the channel of water between Denmark and Sweden, but also created with two channels, known as the Great Belt and the Little Belt,

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