Prior to that, in late 1690 and early 1691, while the main armies went into winter quarters, an area east of the Shannon became a zone of contention which was ruinous to the local population caught between the two forces. The Williamites established small garrisons around which irregular Irish forces, rapparees, and raiding troops from the Jacobite positions operated in small-scale actions. Ballymore however remained the principal forward position for the Jacobites and Sarsfield showed particular concern for its retention as covering the approach to Athlone.