In my book series (link here), Aurea (a planet based on Byzantine Anatolia) is conquered by a group called the Tatians, who have access to technology that would not be out of place in Star Wars (faster-than-light space travel, holograms, orbital bombardments, electricity, internet, etc). Could this planet be fully brought up technologically to their standards by the time their 19-year rule is over?
The Tatians are at war with basically all of the rest of the galaxy (which is loosely united in a shaky alliance centered around the Aureans and the Ishgas). The Ishgas are the only civilization in the galaxy whose technology is on par with that of the Tatians (in fact the Tatians stole their tech from the Ishgas).
Anyway, when the Tatians occupied Aurea, its king (named Weasel) went into hiding on a backwater planet and will not be heard from again until 19 years into the future. Since all of the planets in the alliance besides Ishgabangaloodoo and its farming colonies were under temporary Aurean leadership, the Tatians acquired these planets as well when they took over Aurea. The Tatians swiftly moved to occupy these planets, and within a few days, the Tatians controlled all of the galaxy except for Ishgabangaloodoo and 5 farming colonies under its rule.
However, Aurea was the most resource-rich planet they conquered, causing them to invest the lion's share of their economy into building up its infrastructure. Hundreds of millions of workers were forcibly resettled there. Roads were built. Schools were built. All of the illiterate peasants were put in schools and taught to read. Power grids were set up. Internet servers were installed. Medieval spires were replaced by steel skyscrapers. Spaceports were built in all the major cities, allowing people from other planets to flock to Aurea due to an extreme excess of unfilled jobs. The Tatians even moved their capital to Aurea since they considered the land so beautiful compared to their freezing tundra homeworld. The Tatians operated a command economy, similar to that of the Inca Empire or Ancient Egypt. However, their repression towards basic human rights proved to be their undoing here.
Around 17 years into the occupation, although the planet was advancing technologically like never before, many teenagers began to question the authority they were living under. Despite things like mandatory 2-hours-a-day propaganda radio that managed to brainwash all of the adult ex-peasants into mindlessly obeying their new government, people began using the radio's music channels to express their views. Albums like Purple Day's "Tatian Idiot" topped the charts. When the government began imprisoning the people who made this music and shutting down anti-government radio stations, basically the entire youth rose in a massive revolt. The Tatian garrison was overwhelmed and completely wiped out by sheer force of numbers, forcing the Tatians to send in 60 million troops (roughly 1/5 of their entire army) to suppress the rebellion.
During this time, the Tatians relocated their capital back to their icy homeworld to avoid this danger. When the reinforcements arrived, they badly beat the Aurean revolutionaries over the next year until they were on the verge of defeat. When all hope seemed lost, the Aurean Alliance (a group, centered around Ishgabangaloodoo that had been rebelling against Tatian rule in the northeast of the galaxy) had found Weasel in hiding, made him their leader, and began an all-out attack on Aurea that worked together with the revolutionaries to liberate the planet.
When the planet was liberated, the new Tatian institutions were kept in place with some major modifications: The economy was changed from a command system to a mixed system, similar to that of the modern USA, meaning things such as factories and farms were now privately owned, but still regulated by the government. However, the propaganda radio was abolished, and the Tatian government was replaced by a Democratic system.