"THE MAN WHO was known for years in the Portobello Road area as 'Colonel Pyat' or sometimes simply as 'the old Pole', and who, in the 60s and 70s, was Mrs Cornelius's regular evening consort at The Blenheim Arms, The Portobello Castle and The Elgin (her favourite public houses), collapsed during the August 1977 Notting Hill Carnival when a group of black boys and girls collecting for Help the Aged in Carribean fancy dress entered his shop (one of the few open) and demanded a contribution. His heart had failed him. He died at St Charles Hospital some hours later. He had no next of kin. Eventually, following a great deal of unpleasant publicity, I inherited his papers1."
Thus does Michael Moorcock begin the preface to his 1981 novel about the checkered career of "Maxim Arturovitch Pyatnitski", aka "Dimitri Mitrofanovich Kryscheff", aka many, many other things.

Presented as an autobiography, Colonel Pyat traces his life from his early childhood in turn-of-the-century Kiev2, until the time he flees Russia for good around 1920 during the Russian Civil War.  It is a tale of a precocious if self-centered child striving to fulfill his imagined potential, but being swept along by events with everyone else. We are led through such a labyrinth of bombast, projection, self-deception, betrayal, degradation, assertions of cleverness, deeds of valor, and academic achievement, all while the Russian Empire is dissolving in a maelstrom, that it becomes difficult to tell what is truth and what is a lie3.

This is classic Moorcock, and then again it is a whole different kettle of borscht. Like many Moorcockian anti-heroes, you will intensely dislike4 Colonel Pyat, all the while hungering for his next exploit.  On the other hand, you will not be able to knock this novel off in an afternoon as you did with his Elric novels.

There is little of The Eternal Champion to Colonel Pyat, despite the tie-in via Mrs Cornelius. Russia during the Revolution is kaleidoscopic enough to constitute a multiverse all by itself.  Byzantium Endures is followed by the 1984 sequel The Laughter of Carthage, and finally 1992's Jerusalem Commands  (neither of which I have read).

1Mr. Moorcock graciously provides us with facsimiles and transcripts of these manuscripts, providing insight into the character of Colonel Pyat.  These excerpts are somewhat disassociative.
2This is the source of our title; Russia has styled itself the successor to Byzantium many times throughout the modern era.
3Well, this being fiction, of course it is all lies.
4Make no bones about it, Pyat is a product of his times and culture. His mother raises him to believe his father is a Cossack hetman, not the bastard offspring of a transient Jewish radical (possibly his gang-leader "uncle" Semyon, possibly Trotsky) as everyone else assumes. This identity confusion is a constant theme throughout the book and is the source of his hatred of all races except the one be imagines himself to belong to.