"historically" controlled by many countries but never by China... prior to Xi there were other Chinese rulers, none had the Taiwan obsession as Xi has, some recent Chinese rulers Deng Xiaoping, Hu Jintao never worry too much about Taiwan, they worried about keeping the country safe and stable, not looking for antagonism contrary to Xi. Back in 2015 Xi was asked about his intentions in SCS if he intended to built military bases there he point blank said no, look at it now, very similar to Putin when asked if he was invading Ukraine or back in 2014 if he was invading Crimea in both cases the answer was no, for me Xi has absolutely no credibility, lived there long enough to know how it works, Xi claimed that China would rise peacefully
below link related to Xi 2015 comments
Behind Public Assurances, Xi Jinping Spreads Grim Views on U.S
https://news.yahoo.com/behind-public-assurances-xi-jinping-130327081.html?fr=sycsrp_catchall
What are China’s leaders saying about the South China Sea?
https://www.lowyinstitute.org/the-interpreter/what-are-china-s-leaders-saying-about-south-china-sea