peace proved so elusive. There were a number of reasons for this. When the Treaty of Westphalia was signed in 1648, the Franco-Swedish alliance still had over 84,000 men under arms on Imperial territory, their opponents around 77,000; while relatively small in modern terms, such numbers were unprecedented at the time. With the possible exception of Spain, the 17th century state could not support armies of this size, forcing them to depend on "contributions" levied or extorted from areas they passed through. Obtaining supplies thus became the limiting factor in campaign planning, an issue that grew more acute later in the war when much of the Empire had already been fought over. Even when adequate provisions could be gathered, the next problem was getting them to the troops; to ensure security of supply, commanders were forced to stay close to rivers, then the primary means of bulk transportation, and could not move too far from their main bases. Many historians argue feeding the troops became an objective in itself, unconnected to diplomatic goals and largely uncontrolled by their central governments. The result was "armies increasingly devoid of intelligible political objectives...degenerating into travelling armed mobs living in a symbiotic relationship with the countryside they passed through". This lack of connection often worked against the political aims of their employers; the devastation inflicted in 1628 and 1629 by Imperial troops on Brandenburg and Saxony, both nominally their allies, was a major factor in their support for Swedish intervention. Social and cultural impact It has been suggested the breakdown of social order caused by the war was often more significant and longer lasting than the immediate damage. The collapse of local government created landless peasants, who banded together to protect themselves from the soldiers of both sides, and led to widespread rebellions in Upper Austria, Bavaria and Brandenburg. Soldiers devastated one area before moving on, leaving large tracts of land empty of people and changing the ecosystem. Food shortages were worsened by an explosion in the rodent population, while Bavaria was overrun by wolves in the winter of 1638, and its crops destroyed by packs of wild pigs the following spring. Contemporaries spoke of a 'frenzy of despair' as people sought to make sense of the relentless and often random bloodshed unleashed by the war. Attributed by religious authorities to divine retribution for sin, attempts to identify a supernatural cause led to a