The religious division between ireland and england began with the?

Ireland became part of the United Kingdom in 1801. But Ireland’s sectarian divisions, which had opened up during religious wars in the 17th century between Protestants and Catholics, were exacerbated by economic problems in the 19th century. Britain’s shift to free trade from the 1840s onwards mainly benefited the industrial north-east of Ulster, where Protestants made up a majority of the population. But the rest of the country, which was more reliant on agriculture, suffered badly from falling global food prices and the Irish Famine of 1845-50. The result was the rise of Irish nationalist movements, drawing much of their support from the Catholic south, which wanted a new Irish Parliament and to re-introduce protectionist measures. When William Gladstone, then Britain’s prime minister, proposed Irish legislative independence (called Home Rule) in 1885, the north-east exploded with sectarian rioting against his proposals. Ulster Protestants feared that “Home Rule means Rome Rule”, thinking they would lose the religious and economic freedoms they enjoyed as part of the United Kingdom by becoming a minority in a mainly Catholic Ireland. When the rest of Ireland gained independence as the “Irish Free State” in 1922, north-east Ulster did not want to join them. The British government was forced to partition the six most north-eastern counties of the new Irish state to form Northern Ireland, in fear that Protestant civil unrest in Ulster would otherwise turn into a civil war against the new state.

a and b because with the other three, they simplify to something else.