The enduring importance of Cromwell's administration for Irish history lies not only in what it achieved – the ending of the hegemony of the Anglo-Irish magnates and the revival of crown government – but also in the hostile reaction it provoked. The liberal experiment of the 1540s must be examined in the light of the reaction to the Cromwellian settlement of the 1530s. In bringing down the curtain on the medieval Lordship, Cromwell set the scene for the establishment of the sovereign kingdom.

The settlement unsettled – Cromwellian reform and the loyal community

In examining the resistance to Cromwellian reform within the loyal Anglo-Irish community, attention tends to be concentrated on two episodes, the Kildare rebellion and the religious Reformation. But it can be said at once that as manifestations of popular reaction within the colony against Cromwell's Irish policy these have the least significance.

Although the Kildare rebellion occurred before the full Cromwellian programme was launched, it was precipitated by that series of events in 1533 and the spring of 1534 which prepared the way for the inauguration of the programme. It was essentially, therefore, a reaction to Cromwell's Irish policy. The more closely the Kildare rebellion is observed, the more neatly it falls into the category of late medieval dynastic warfare. Silken Thomas was able to elicit the support of his father's Gaelic allies, and of most of his kinsmen, feudal underlords and tenants. He was able to bully many landholders in the Pale into neutrality or even support, by guaranteeing indemnity to their property. However, the ease with which the alliance disintegrated reflects the considerations of political expediency and local self-interest on which it was based.