settlers. The biggest was the Plantation of Ulster, which utilised estates confiscated from the northern lords who went into exile in 1607. Around 80% of these were distributed to English-speaking Protestants, with the remainder going to "deserving" native Irish lords and clans. By 1641, the economic impact of the plantations on the native Irish population was exacerbated because many who retained their estates had to sell them due to poor management and the debts they incurred. This erosion of their status and influence saw them prepared to join a rebellion, even if they risked losing more. Many of the exiles, such as Eoghan Ruadh Ó Néill, served in the Catholic armies of France and Spain, particularly the Army of Flanders. They formed a small émigré Irish community, militantly hostile to the English-run Protestant state in Ireland, but restrained by the generally good relations England had with Spain and France after 1604. In Ireland itself, resentment caused by the plantations was one of the main causes for the outbreak and spread of the rebellion, combined with Poynings' Law, which required Irish legislation to be approved by the Privy Council of England. The Protestant-dominated administration took opportunities to confiscate more land from longstanding Catholic landowners. In the late 1630s Thomas Wentworth, the Lord Deputy of Ireland, proposed a new round of plantations designed to expand Protestant cultural and religious dominance. Delays in their implementation caused by Charles' struggles with his political opponents in England and Scotland meant that Catholics still owned over 60% of land in 1641. Religious discrimination Most of the Irish Catholic upper classes were not opposed to the sovereignty of Charles I over Ireland but wanted to be full subjects and maintain their pre-eminent position in Irish society. This was prevented by their religion and the threat of losing their land in the Plantations. The failed Gunpowder Plot of 1605 had led to further discrimination against, and mistrust of, Catholics. The Protestant Church of Ireland was the only approved form of worship, although it was a minority even among Irish Protestants, many of whom were Presbyterians. Both they and the majority Catholic population were required to pay tithes to the church, causing great resentment, while practicing Catholicism in public could lead to arrest, and non-attendance at Protestant service was punishable by recusant fines. Catholics could not hold senior offices of state, or serve above a certain rank in the