It has some basis in Chinese history
General Tso/Gau/Gao actually existed! His name in Chinese was Zuo Zongtang, and he was a military man during the Qing dynasty. Dude quelled the Dungan revolt in the 1800s (that was huge), but it's not known whether he's the one who first made the chicken, or whether some admirer of his just wanted to name a hot dish after him.
Also, sweet & sour sauce isn't truly Chinese. But they do have claim to an older, less potent, more vinegary version that's straight outta Hunan province. Bizarrely, ours is more popular in China today.