The Stars, Like Dust

Blurb

The Stars, Like Dust is a 1951 science fiction mystery book by writer Isaac Asimov.
The book is part of Asimov's Galactic Empire series. It takes place before the actual founding of the Galactic Empire, and even before Trantor has become important. It starts with a young man attending the University of Earth. Biron Farrill is the son of the greatest nobleman on the planet Nephelos, one of the Nebula Kingdoms. The story starts with the news that his father has been caught conspiring against the Tyranni.
The Tyranni are a minor empire that rule fifty planets near the Horsehead Nebula. Tyrann suppressed science and space-navigation training in the Kingdoms, to help maintain control over its subject worlds. The ruler of Tyrann in the story is called the "Khan". Asimov obviously took the Mongol dominion over the Russian principalities as a model, much as he used the declining Roman Empire for his Foundation series.
The story's in-universe historical context is generally regarded as quite interesting, during the long period between the initial expansion and the rise of the Empire of Trantor.