In October 1641, violence erupted in mid-Ulster that spread throughout the whole kingdom and lasted for more than a decade. The war was neither unpredictable nor was it out of step with the rest of the Stuart kingdoms, or indeed Europe generally. As with all wars, particularly the multi-national and multi-denominational, the Irish wars of the 1640s and 1650s had many complex and interrelated causes. Law, the legal system and the legal community played a vital role in the origins and the development of the conflict in Ireland that took it from a dependent kingdom to becoming part of a republican commonwealth. Lawyers also played a fundamental part in the return of the legal and political 'normality' in the 1660s. This collection of essays considers how the law was part of this process and to what extent it was shaped by the revolutionary developments of the period. These essays arise from a conference held in 2014 in the House of Lords at the Bank of Ireland, Dublin, under the auspices of the Irish Legal History Society.