Great Tang: Your Majesty, Please Come Out of Retirement!

After transmigrating to the Tang Dynasty, he subdued the Thirty-Six Kingdoms of the Western Regions while escorting a princess on a marriage alliance mission, then went as an envoy to Tibet and captured the father of Songtsen Gampo alive!

In his spare time, he built curved-shaft plows, made salt, smelted iron, served as an imperial inspector, and tinkered with inventions. Before he knew it, his fame had spread all the way to Great Britain, which was still in the Middle Ages.

Li Shimin came in person to ask Qin Lihuan to enter public service, but Qin Lihuan just waved his hand and said, "I'm merely a country bumpkin, ignorant of military and political affairs. I would be of no benefit to the nation!"

Li Shimin said bitterly and helplessly, "My dear subject, stop pretending. You've already conquered ten kingdoms and unified the world's systems of weights and measures..."