Short story (maybe by Poul Anderson) with technically-innovative pirates trying to overthrow a city on a post-apocalyptic Earth

Question

After some kind of Earth disaster a new civilization starts exploring Earth again in order to look for other cultures. The captain of a ship finds two of them at once: a friendly, civilized and sophisticated culture, where tradition triumphs over innovation, living in a beautiful city - and a technically innovative culture, which unfortunately consists of pirates trying to take over the city.

I'm quite sure it was from Poul Anderson: the story had a brilliant account of the different points of view with a good portion of irony and a final twist.

The city's governor's daughter agrees to serve as a bait in a stratagem of the exploring captain, her guest, so that he can capture the pirate commander and save her city.

After that, she expects that he kills the pirate in order to avenge her honour, but the captain is interested in the innovative skills of the pirates and forms an alliance with them - and has no clue regarding her subsequent anger.

I don't remember what kind of ships they used.

Answer 1

Poul Anderson's short story "The Sky People" (copyright 1959, first published in The Magazine of Fantasy and Science Fiction) features the story of raiders in hydrogen buoyancy airships attacking a genteel city that is playing host to a sailing ship of "the sea people" (Maurai). The sea people are relatively technologically advanced and the ship is a long-range exploration and contact vessel.

The story opens from the point of view of the raiders

The rover fleet got there just before sunrise. From its height, five thousand feet, the land was blueish gray, smoked with mists. Irrigation canals caught the first light as if they were full of mercury. Westward the ocean gleame, its far edge dissolved into purple and a few stars.

Loklann sunna Holber leaned over the galley rail of his flagship and pointed a telescope at the city. [...]

The city dwellers are educated and value education

You speak our language most excellently, S'ñor," said Doñita Tresa Carabán. She smiled, "Perhaps better than we, since you studied texts centuries old before embarking, and the Spañol has changed greatly since.

but have little technological prowess

"You have so much more than we," she said wistfully. You have told me how your ships can sail unbelievably fast, almost into the wind [...] how you farm the ocean for food and fiber and [...] that even small children on the loniest island can read and have printed books [...] that you have none of the sicknesses which destroy us.

The raider's initial attack is repelled by the combined efforts of the city dwellers and the sea people, but they do not withdraw. A plot is hatched to draw in the remaining raiders but it calls for the risk of one of the ladies of the court:

"Then someone must go to them. [...] A woman—not any woman, but a very beautiful one—would she not soon be taken to their chief?"

In the end the Maurai and the city dwellers defeat the raider entirely and rescue the hostage who has suffered no debilitating physical injury. The future looks bright for cooperation between the sea people and the city dwellers, but the twist is the Maurai Captain's opinion his government will only offer the city dwellers an alliance to further their ends of supporting the development of the sky people. Explanations for this are offered but do not console the city dwellers whose fondest hope is to wipe out the raiders entirely.