In his fine survey of the last half-millennium of Irish history, Dublin writer John Gibney makes the enormously complicated—and usually quite tragic—story of Ireland’s past understandable. A Short History of Ireland is a concise and highly readable account that starts with the Protestant Reformation and ends more or less in our own day. The book has five parts, one for each of the centuries he discusses, further divided into chapters exploring major themes. Each of the five parts closes with a section called “Where Historians Disagree,” exploring points of scholarly contention.

The first of these disputed historical questions is: “Why did the Reformation not succeed” in Ireland? At the time Gibney’s chronicle begins, the population of the island of Ireland was predominantly Gaelic-speaking and Roman Catholic. Gaelic has declined—it’s still spoken by about 40 percent of the population of the Republic of Ireland and perhaps 5 or 10 percent of the population of Northern Ireland. But Ireland today remains overwhelmingly Catholic: The Republic of Ireland is nearly 80 percent Catholic and even in Northern Ireland the Catholic and Protestant populations are roughly equal at around 40 percent each. Gibney describes several explanations historians have offered for why the reformation didn’t “take” in Ireland. He seems partial to the idea that “the resources simply were not available to fully impose the new Episcopalian state church on a diverse population that remained strongly attached to Catholicism.”