When Axel Oxenstierna, Chancellor of Sweden, died in 1654, Sweden was a great power. In 1612, however, when Oxenstierna took office, Sweden was on the verge of collapse. In the east, she was menaced by Muscovy, in the south-east by Poland, and in the west by Denmark. One of the means to save the Swedish realm was through active diplomacy. Two important figures in Oxenstierna's diplomatic network were the Scottish officer Sir James Spens (d. 1632) and the Dutch humanist and jurist Jan Rutgers (d. 1625), who played central roles in Swedish foreign politics in the crucial period 1613-1632, i.e., from the disastrous peace with Denmark to Sweden's entry into the Thirty Years' War. Spens served as Swedish ambassador in London and as Stuart ambassador to Gustav II Adolf. He played an important part in the various rounds of negotiations in 1624-1625, when statesmen and diplomats were focused on bringing the British, the Swedes, the Danes, and the Dutch into a grand alliance to defend the Protestant cause against the Habsburgs and the Catholics. We learn from his letters that he was becoming more and more suspicious of Charles I and the Duke of Buckingham. Rutgers served as Swedish representative in the Dutch Republic and as emissary to North German princes. His most dramatic mission was that to Prague in 1620, from where he reported in a series of letters on the Bohemian adventure of Elector Palatine Frederick V. Rutgers' letters give us an insight into his varied diplomatic activities, and glimpses of Oxenstierna's policies and diplomatic methods. Spens' and Rutgers' letters are edited with introductions, summaries, notes and index in English. Two letters by Spens are in Scots. Arne Jönsson is professor of Latin at Lund University. He is specialized in historical-philological research. Between 1999 and 2005 he worked as a research editor at the Swedish National Archives and the Lund Regional Archives.