In his memoirs, Rome's first emperor, Augustus, can proudly recount how during his reign at the beginning of our era, he sought contact with the peoples of the north, at the edge of the world. One hundred and fifty years later, the Greek geographer Ptolemy's world map shows that the Ro-mans began trading with the Germans in the Baltic Sea. He names trading posts that we can still visit today. The Germans had sought after goods for the necessities of life to offer, but also luxury goods with timeless beauty. The method of counting twelve is gaining an early foothold in the Baltic Sea region, as a result of Roman trade activities. When the Western Roman Empire collapses at the end of the 5th century, their way of calculating is taken over by the Franks and the British, who both cre-ate robust coin economies with the Roman calculation as a basis. The expansion of the Arab world beginning in the 7th century does not go unnoticed in the world of the Vikings. From the eighth century, large finds of silver are made in the Middle East and the Arabs mint coins from the metal they quarry. Via European, Polish and Russian rivers, the coins finally reach the Baltic Sea. In the early ninth century, the Arab Caliphate introduced a new method of counting. They use numbers and position counting. It would not be until the 13th century that Europe became aware of the Arabic way of calculating and another 500 years before the system became widely accepted in the Western world. The Arabian silver becomes an exotic parenthesis in the Baltic Sea trade system and the silver flow decreases, at the same time as the Viking Age ends at the end of the first millennium of our era. The inability of the northerners to recoup their laboriously acquired capital from silver coins is reflected in the silver treasures with Arabic coins, which the Vikings store and which constantly appear in our time during archaeologists' excavations on Gotland and along the shores of the Baltic Sea.