The level of esoteric understanding Tolkien has is pretty impressive.
I wonder from where did he get it. Interesting that nobody asked that question. There are some similarities in his symbols with some masonic and rosicrucian symbols. Then there is this rumor, but it's only a rumor that he was initiated in Golden Dawn with C.S. Lewis (that is author of Narnia). Then one thing that got in my eye is that his family dealt with banking businesses in England that didn't turn well. It's gets more interesting when you found that his aunt Grace told him history of his surname, which was originally "von Hohenzollern". (German dynasty in control of Prussia, later German empire.) In the time when the Vienna was under Turkish siege in 1526. George von Hohenzollern led successful attack against Turks, so he got nickname Tollkühn, which means "crazily brave". The family had probably also had connections to french nobility, french version of his surname was du Téméraire, his aunt told him that his family made their family name English so they could escape guillotine in the time of French revolution. His story about Numenor was inspired by Atlantis and there is similarity with Sumerian myth so he didn't use only myths of Northern people. Maybe he got it from unconscious memory(or got it beamed up in his head is higher probability) or maybe he was insider. Makes you wonder?