The story appeared in Isaac Asimov’s SF Magazine in 1978 and 1979 and was first published by Nelson Doubleday in 1980.
Several editions: Hardcover and Paperback.
" A circus starship stranded it’s troupe on a distant planet in an unknown star system where, without an audience, the members of this unique social seed made do, survived, and begat. Discovered two centuries later where it has become the focus of warring galactic powers, human Earth ambassador Lord Ashly Allenby is charged with bringing the Planet Momus into the Quadrant against the Warlords of the Tenth. The only problem is, he can’t get anyone to listen to his important message until he develops an act worth watching. How the population of Momus becomes a part of the wider galaxy is told through a series of stories, beginning with "The Tryouts," which was my very first story sale."