(Via Fark) That would be Norton I, Emperor of the United States and Protector of Mexico. Those of you who have not been so fortunate as to have been taught proper American history may peruse his history and accomplishments here: a copy of his famous proclamation may be found below.
17 September 1859
At the peremptory request of a large majority of the citizens of these United States, I, Joshua Norton, formerly of Algoa Bay, Cape of Good Hope, and now for the past nine years and ten months of San Francisco, California, declare and proclaim myself Emperor of these U.S., and in virtue of the authority thereby in me vested, DO HEREBY order and direct the representatives of the different States of the Union to assemble in the Musical Hall of this city on the 1st day of February next, then and there to make such alterations in the existing laws of the Union as may ameliorate the evils under which the country is laboring, and thereby cause confidence to exist, both at home and abroad, in our stability and integrity.
Probably the best modern testimonial for his Imperial Majesty was done by Neil Gaiman, although R. Talsorian Games gave it a very credible shot. And I don’t have much else to say on the topic, except that very few people ever had an unkind word for Norton I, and none of them had them twice in public.