The main legacy of the French revolution was nationalism, the demand for separate nation states independent of multi-national and multi-lingual empires. Irish nationalism was no exception. Its first early manifestation was the 1798 Rebellion, but the actual form that nationalism took in the course of the nineteenth century relied less on abstract principle than on a demand for Catholic rights. This proved difficult in the context of the pan-Protestant United Kingdom. The Famine of the 1840s represented the great breach with old ways. The death and emigration of two million of Ireland's poorest was a human tragedy on a vast scale, but it prepared the way for a modern agricultural and trading system as well as increasing bitterness against the British government. In the meantime, Ulster was transformed by the industrial revolution, growing ever more prosperous and remote from the agrarian south. The eventual result was the separation of the mainly Catholic south from the United Kingdom and the establishment of an independent Ireland, but one partitioned from the mainly Protestant north, which remained in the United Kingdom. Richard Killeen's Concise History of Modern Ireland makes complicated history simple, but not dumbed down.