Alexander Pushkin (2.1) is considered to be one of the greatest Russian literary figures of all time, but watch out—those lines Poprishchin quotes are actually not from Pushkin. They're from a not-so-important writer called N.P. Nikolev.
Philip II, the King of Spain (12.1), who was a real Spanish king in the 16th century
The problems with the succession to the Spanish throne (10.1) actually did happen. On September 29, 1833, Ferdinand VII of Spain died, and the throne was given to his three-year-old daughter Isabella. But her uncle didn't like this one bit and the result was political chaos.
Pop Culture References
The journal The Northern Bee (2.1), which was the most popular news magazine of the time
The Russian fool Filatka (4.1), who was a stock folk character in popular vaudevilles of the time