3,600 horse, but the outbreak of the First English Civil War in August 1642 ended the flow of reinforcements and money from England and a military stalemate ensued. Founding of the Confederation By early 1642, there were four main concentrations of rebel forces; in Ulster under Felim O'Neill, in the Pale around Dublin led by Viscount Gormanston, in the south-east, led by the Butler family – in particular Lord Mountgarret, and in the south-west, led by Donagh MacCarthy, Viscount Muskerry. 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. Within a few months of the rebellion's outbreak, almost all of the Catholic gentry had joined it, including the Anglo-Irish Catholics. There are three main reasons for this. First, local lords and landowners raised armed units of their dependents to control the violence that was engulfing the country, fearing that after the settlers were gone, the Irish peasantry would turn on them as well. Secondly, the Long Parliament and the Irish administration, and King Charles, made it clear that Irish Catholics who did not demonstrate their loyalty would be held responsible for the rebellion and killings of settlers, and would confiscate their lands under the Adventurers Act, agreed on 19 March 1642. The old policy of issuing pardons to stop conflicts was ended, and the rebel leaders were outlawed on 1 January 1642. Thirdly, it looked initially as if the rebels would be successful after they defeated a government force at Julianstown in November 1641. This perception was soon shattered when the rebels failed to take nearby Drogheda, but by then most of the Catholic gentry had already committed themselves to rebellion. The Catholic gentry around Dublin, known as the "Lords of the Pale", issued their Remonstrance to the king on 17 March 1642 at Trim, County Meath. Hugh O'Reilly (Archbishop of Armagh) held a synod of Irish bishops at Kells, County Meath in March 1642, where a majority declared that the ongoing conflict was a "holy and just war". On 10 May 1642, Archbishop O'Reilly convened another synod at Kilkenny. Present were 3 archbishops, 11 bishops or their representatives, and other dignitaries. They drafted the Confederate Oath of Association and called on all Catholics in Ireland to take it. Those who took the oath swore allegiance to Charles I and vowed