An Elephant in the Womb

I have just finished Andrew Robert's magisterial, and short, book on the battle of Waterloo, and a splendid rendition of the events it is. I must recount two specific points, one a criticism, and one a superb anecdote.
The criticism is that Robert's continues to talk about Belgian troops. Which is an odd anachronism, seeing as how there was no such place as Belgium at the time of the battle, and wouldn't be for another 15 years. Indeed the French speaking troops in the allied force had been serving under Napoleon less than two years before the battle. (As had many of the Dutch speaking troops for that matter).
The anecdote however deserves to be quoted in full. Prince Gebhard von Blücher, the seventy three year old Commander in Chief of the Prussian army was an impressive fellow, going by the nickname of "Marshal Vorwärts". However he had a couple of issues,

"Not everything about Blücher inspired confidence, however, since he suffered from occasional mental disturbances, including the delusions that he had been impregnated by an elephant and that the French had bribed his servants to heat the floors of his room so that he would burn his feet. The Prussian high command nonetheless exhibited a commendably broad/minded attitude towards these disorders; their army chief of staff General Gerhard von Scharnhorst wrote that Blücher 'must lead though he has a hundred elephants inside him'.