When King Gustavus died in November 1632, his only legitimate and surviving child, Christina, was almost six years old. Until her declaration of majority at 18, a regency council ruled Sweden. This council was headed by Lord High Chancellor Oxenstierna, who wrote Instrument of Government (1634), a new constitution. During the years after the king's death, it became apparent that differences of opinion existed within the council. Some of Oxenstierna's colleagues recommended that Sweden should seek peace and withdraw from the war in Germany, not least after the defeat at Nördlingen in 1634. However, Oxenstierna's opinion, that Sweden should remain in the war to ensure compensation for the sacrifices made, prevailed. The, for the Swedish side, disastrous outcome at Nördlingen brought him, for an instant, to the verge of ruin and compelled him for the first time so far to depart from his policy of independence as to solicit direct assistance from France. But, well aware that Richelieu needed the Swedish armies as much as he himself needed money, he refused at the Conference of Compiègne in 1635 to bind his hands in the future for the sake of some slight present relief. In 1636, nevertheless, he concluded a fresh subsidy-treaty with France at Wismar. Swedish troops remained in Germany all the way until 1648 and the Thirty Years' War's end. Oxenstierna, however, left Germany and returned to Stockholm in 1636, after ten years duty as premier Swedish representative in Prussia and Germany.