There are stark contrasts between the experiences of Warwickshire before and after the outbreak of the Civil War. In place of the established leaders of county society who formed the commission of the peace in the 1620s and 1630s, a parliamentarian county committee, consisting of comparatively obscure men, took control of the county. The responsibilities of Warwickshire's rulers were as different as their personnel: instead of the comparative routine of the pre-1642 period they were faced with the hectic demands of military administration in a frontier area. Parliament controlled the main body of the county throughout the Civil War but its hold was always precarious: neighbouring royalist garrison continually raided Warwickshire and levied contributions on many border parishes. The county was the site of one major battle, Edgehill, and was a frequent thoroughfare for the armies of both sides. Consequently the experiences of the ruled changed as sharply as the duties of the rulers.

There are great differences, also, in the sources available for a study of the county between 1620–42 and 1642–9. For many aspects of the earlier period, the sources are inadequate but for the Civil War period the sheer bulk of material that survives for the military administration of the county creates problems in itself. There are many hundreds of letters, warrants and orders of the county committee, and many scores of working accounts of civilian officials and military commanders. Much of this material is of a random rather than systematic nature: there is, for example, just one surviving order book of the county committee, starting after the war was over, and covering sequestration business only.