convert named Owen O'Connolly. He promptly informed one of the Lord Justices, and MacMahon and Maguire were arrested, while the remaining plotters slipped out of Dublin. Warnings of an imminent rising had also been communicated to Dublin by Sir William Cole. Despite this failure, the rebellion in Ulster went ahead and Felim O'Neill and his allies, including Rory Maguire, quickly captured positions throughout the province, including Dungannon, Charlemont Fort, Newry, Tandragee, Portadown, Mountjoy Castle, Castleblaney and Carrickmacross. Those that did not surrender, such as Enniskillen Castle, were besieged and within two days the insurgents held most of counties Armagh, Tyrone, Fermanagh and Monaghan. The Proclamation of Dungannon, issued by O'Neill on 24 October, stated they had taken up arms only to defend their freedoms and meant no harm to the king's subjects. This was followed on 4 November by the Newry declaration which claimed Charles had approved the rising to secure Ireland against his opponents in England. Although the declaration is now accepted as a forgery, many of the Anglo-Catholic gentry were dismayed by indiscriminate anti-Catholic measures taken by the Dublin authorities, including those who had initially condemned the rebellion. The suspension of the Irish Parliament on 17 November deprived them of the political means to resolve these issues and the declaration provided cover for moderates such as Nicholas Plunkett to make common cause with the rebels. Rumours also circulated that radical Protestants were seeking to replace Charles I with his exiled German nephew the Elector Palatine, paving the way for increased repression of Irish Catholics. The influential Lords of the Pale joined the rising in early December, while rebels in Cavan were led by Philip O'Reilly, the local Member of Parliament, and Mulmore O'Reilly, the High Sheriff. Dundalk was occupied, while an army under Brian McMahon moved south from Ulster towards Dublin and on 21 November besieged Drogheda from the north. Others advanced through County Meath and blockaded the town from the south, then defeated a relief force sent from Dublin at Julianstown on 29 November, inflicting over 600 casualties. On 28 November, around 8,000 rebels besieged Lisnagarvey but after losing some 300 men in an unsuccessful assault, they set fire to the town and retreated. This setback and the stubbornness displayed by the town's defenders allegedly made a deep impression on the attackers, since it showed hopes of a quick and relatively painless victory in Ulster were over