Dahl trained in Sweden but at the age of 23 came to England and between 1682 and 1683 according to Vertue was an associate or pupil of Godfrey Kneller. In 1685 he left England for France and Italy, studying in Rome for two years. Here he converted to Roman Catholicism and gravitated towards the circle of Queen Christina who while resident in Rome had also converted. In 1685 Dahl secured a commission to paint a portrait of Queen Christina (Grimthorpe Castle, Duke of Ancaster Collection, canvas 50 x 40 inches) which secured him instant success not only in Rome but also in England on his return there in 1688 - 89. Many of Dahl’s new clients in London were Swedish émigrés and diplomats and he rapidly became one of this closely-knit Swedish circle.