Perhaps this is an American way of thinking, but I always thought that "throne" would be inextricable from "altar." When I think of famous 'atheists' from ye olden days I automatically think of Thomas Paine and Voltaire, who railed against the ancien regimes of their respective countries (of origin) and, at least in Paine's case, against the 'divine right of kings' in general.

My dim impression of the mid-late 19th century is that Darwin came along, along with various other thinkers, and there was a massive upsurge of atheism, agnosticism, skepticism, and general secularism, at least among the elites. And yet it took until the Great War for the "Crowned Heads" to either take a backseat or to be deposed altogether. Whereas in feudal times, and into the Renaissance/Reformation and Baroque eras, the kingpin (pun intended) to the whole thing, from the Holy Roman Emperor all the way down to the pettiest baronet, was "divine right."

How off are my assumptions? And how much of a threat was the rising tide of secularism to the institution of royalty/aristocracy prior to the Great War?