 Bengt Bengtsson was a member of the influential Oxenstierna family and was born in 1591 to Bengt Gabrielsson Oxenstierna the Elder, councillor to Charles, Duke of Södermanland, Närke and Värmland (later King Charles IX), and his second wife Brita Posse.As was customary in the Oxenstierna family, he was educated abroad and spent the years 1607-13 travelling the European continent, studying at the German universities of Rostock, Jena and Wittenberg and visiting Poland and Italy.He visited Palestine in 1613 but was robbed and returned impoverished to Italy, where he entered the service of the Grand Duke of Tuscany, Cosimo II de' Medici.