From 1641 to early 1642, the fighting in Ireland was characterised by small bands, raised by local lords or among local people, attacking civilians of opposing ethnic and religious groups. At first, Irish Catholic bands, particularly from Ulster, took the opportunity given them by the collapse of law and order, to settle scores with Protestant settlers who had occupied Irish land in the plantations of Ireland. Initially, the Irish Catholic gentry raised militia forces to try and contain the violence but afterwards, when it was clear that the government in Dublin intended to punish all Catholics for the rebellion  participated in the attacks on Protestants and fought English troops sent to put down the rebellion. In areas where British settlers were concentrated, around Cork, Dublin, Carrickfergus and Derry, they raised their own militia in self-defence and managed to hold off the rebel forces. All sides displayed extreme cruelty in this phase of the war. Around 4,000 Protestants were massacred and a further 12,000 may have died of privation after being driven from their homes. In one notorious incident, the Protestant inhabitants of Portadown were taken captive and then massacred on the bridge in the town. The settlers responded in kind, as did the Government in Dublin, with attacks on the Irish civilian population. Massacres of Catholic civilians occurred at Rathlin Island and elsewhere. The rebels from Ulster defeated a government force at Julianstown, but failed to take nearby Drogheda and were scattered when they advanced on Dublin. By early 1642, there were four main concentrations of rebel forces; in Ulster under Phelim O'Neill, in the Pale around Dublin led by Viscount Gormanstown, in the south-east, led by the Butler family - in particular Lord Mountgarret and in the south-west, led by Donagh MacCarthy, Viscount Muskerry.
How many protestants may have died as a result of the fighting?
16000