At the outbreak of the First Bishops' War, Rossetti's life was threatened. At the behest of the Queen Henrietta Maria gave him refuge in St. James's Palace. Thereafter he was summoned to appear before the House of Commons of England but instead fled England at the end of June 1641. He went to Flanders with the assistance of the Venetian ambassador. His presence at Ghent on 7 September 1641 is established by a letter written by him to one of the Cardinals Barberini, containing a report on the intended colonization of Maryland. He then returned to Rome and to the service of the Barberini.