With a big-R, it’s a philosophical and artistic movement that served as a counterweight to the Enlightenment by advocating for Idealism (versus Materialism) and spirituality (if not necessarily religiosity.)
With a small-R, it’s the skill or proclivity to advance conditions for amorousness.
That’s why capitalization matters.
Mock on, Mock on, Voltaire, Rousseau;
Mock on, Mock on, 'tis all in vain.
You throw the sand against the wind,
And the wind blows it back again.
And every sand becomes a Gem
Reflected in the beams divine;
Blown back, they blind the mocking Eye,
But still in Israel's paths they shine.
The Atoms of Democritus
And Newton's Particles of light
Are sands upon the Red Sea shore
Where Israel's tents do shine so bright.
Tiger Riding for Beginners 