By September 1545, the war was a virtual stalemate; both sides, running low on funds and troops, unsuccessfully sought help from the German Protestants. Henry, Francis, and Charles attempted extensive diplomatic maneuvering to break the deadlock; but none of the three trusted the others, and this had little practical effect. In January 1546, Henry sent the Earl of Hertford to Calais, apparently preparing for an offensive; but one failed to materialize. Francis could not afford to resume a large-scale war, and Henry was concerned only for the disposition of Boulogne. Negotiations between the two resumed on 6 May. On 7 June 1546, the Treaty of Ardres—also known as the Treaty of Camp—was signed by Claude d'Annebault, Pierre Ramon, and Guillaume Bochetel on behalf of Francis, and Viscount Lisle, Baron Paget and Nicholas Wotton on behalf of Henry. By its terms, Henry would retain Boulogne until 1554, then return it in exchange for two million écus; in the meantime, neither side would construct fortifications in the region, and Francis would resume payment of Henry's pensions. Upon hearing the price demanded for Boulogne, the Imperial ambassador told Henry that the city would remain in English hands permanently. During the treaty negotiations, two Protestant mediators—Han Bruno of Metz and Johannes Sturm—were concerned that Henry's war in Scotland was a stumbling block. The sixteenth article of the treaty made Scotland a party to the new peace, and Henry pledged not to attack the Scots again without cause. This gave Scotland a respite from the War of the Rough Wooing, but the fighting would recommence 18 months later.. How many years was between the war being in stalemate and Henry sending the Earl of Hertford to Calais?