This is a funny thing to admit, but I have a soft spot for Timur (Timur-i Lang, known in the medieval West as "Tamerlane"), the late-14th century Mongolian/Turkic warlord who tried to rebuild the Mongolian Empire and didn’t care how many people he had to slaughter to do it. I studied him a bit in graduate school, and I came to respect him despite the excessive violence, in large part because he was incredibly tenacious. This guy was committed, if not to conquering the entire world like the Mongols did, then at least to taking power in his own part of it, and he just kept at it until he succeeded. His tenacity was so great that, despite the fact that he killed and/or sacked half of Asia while he was alive and isn’t particularly well-regarded outside of Uzbekistan (where he’s revered as the national father) and maybe a couple of other places (NOT India), there’s an old Central Asian-Iranian parable about his encounter with an ant that’s meant to show the power of perseverance.
The 14th century was a pretty awful time to be living pretty much anywhere in Asia. The various Mongol khanates were all in steep decline so chaos and anarchy were on the rise and everywhere you looked there was either some Mongolian prince fighting another Mongolian prince (and usually both of them were just puppets for some powerful tribe or another), or (as in China) outright revolution leading to total overthrow. Timur was born into a Mongolian tribe in the city of Shahr-i Sabz (literally “The City of Green”), located in modern Uzbekistan, in 1336. He lived in the settled half of what had once been a unified khanate but that had split into two parts, largely on settled/nomadic lines.
Timur, who had ambition but only mid-level status in the tribe, attached himself to a nomadic warlord who invaded the Shahr-i Sabz region around 1360 and was apparently useful enough to get that warlord to appoint Timur as the head of his tribe, the Barlas. He seems to have already attracted to himself a band of followers who were personally loyal to him rather than bound by custom or tribal requirement, and this made him a force to be reckoned with. Timur set about building his power base at the expense of the warlord who had installed him, until that warlord came back and forced Timur to submit. He went back and forth like this for a decade, first with the nomadic warlords and then with his former partner within the khanate, Amir Husayn, alternately taking power and being beaten back and forced to run and hide.
It was at one of his ebbs, on the run from a battle that had gone against him, that Timur is said to have taken shelter either in some old ruins or a stand of trees and, lamenting his fate, watched an ant carrying a grain of rice that was at least twice its size up the side of a collapsed wall (or tree, depending on the version of the story). Time after time the ant, struggling with its footing and the size of its cargo, fell back down to the ground, only to get up again and start the climb all over again. Timur could certainly empathize with this ant, having tried over and over again to take power only to be driven back each time, and, tired and hungry and with nothing better to do, he kept watching this ant and feeling sorrier and sorrier for himself.
Finally, though, on the 20th (50th, 70th, again it depends) attempt, the little ant managed to carry its prize all the way up the wall and on its way back to the nest, and Timur found new inspiration. If an ant can persevere like this, he thought, then surely a man can do the same, let alone a Great Man as Timur was sure he was. He resolved that he would never again lose hope, and eventually, around 1370 (the story with the ant is apocryphal but I swear the rest is true), he defeated his rivals and took control of both his tribe and the khanate. By the time he died, in 1405, Timur had built his own empire from Central Asia to Iraq, had broken the the nascent Ottoman principality in Anatolia (they got better) and the rival Mongol Golden Horde on the Russian steppe (they really didn’t), and had beaten and made vassals of the Egyptian Mamluks and the rulers of Delhi/Northern India. He died shortly after starting a campaign to conquer China.
It's a nice story about the power of perseverance, even if Timur himself was not such a nice guy.
(slightly adapted from my original)