Protestant aristocrats. The key founders included Wolfe Tone, Thomas Russell, Henry Joy McCracken, James Napper Tandy, and Samuel Neilson. By 1797, the Society of United Irishmen had around 100,000 members. Crossing the religious divide in Ireland, it had a mixed membership of Catholics, Presbyterians, and even Anglicans from the Protestant Ascendancy. It also attracted support and membership from Catholic agrarian resistance groups, such as the Defenders organisation, who were eventually incorporated into the Society. The Irish Rebellion of 1798 began on 23 May, with the first clashes taking place in County Kildare on 24 May, before spreading throughout Leinster, as well as County Antrim and other areas of the country. French soldiers landed in Killala on 22 August and participated in the fighting on the rebels' side. Even though they had considerable success against British forces in County Wexford, rebel forces were eventually defeated. Key figures in the organisation were arrested and executed. Acts of Union Though the Rebellion of 1798 was eventually crushed, small republican guerrilla campaigns against the British Army continued for a short time afterward in the Wicklow Mountains under the leadership of Michael Dwyer and Joseph Holt, involving attacks on small parties of yeomen. These activities were perceived by some to be merely "the dying echoes of an old convulsion", but others feared further large-scale uprisings, due to the United Irishmen continuing to attract large numbers of Catholics in rural areas of the country and arms raids being carried out on a nightly basis. It was also feared that rebels would again seek military aid from French troops, and another rising was expected take place by 10 April. This perceived threat of further rebellion resulted in the Parliamentary Union between the Kingdom of Great Britain and Ireland. After some uncertainty, the Irish Parliament voted to abolish itself in the Acts of Union 1800, forming the United Kingdom of Great Britain and Ireland, by a vote of 158 to 115. A number of tactics were used to achieve this end. Lord Castlereagh and Charles Cornwallis were known to use bribery extensively. In all, a total of sixteen Irish borough-owners were granted British peerages. A further twenty-eight new Irish peerages were created, while twenty existing Irish peerages increased in rank. Furthermore, the government of Great Britain sought to replace Irish politicians in the Irish parliament with pro-Union politicians, and rewards were granted to those that vacated their seats,