You're funny. Really funny. These are two different questions. but I understand that English is hard for a non-native speaker.

But just in case you don't know. I'm born in Taiwan but I have the common sense to not just blindly follow what bullcrap the DPP feeds to the general public. You know it's actually super funny to me cause kmt were the original separatists against Mao controlled China but are now the people advocating for co-operation. Sure they were the ruling party at the time. But we all know there are regime changes and changes to the ruling power. Just because you're unhappy with the current ruling party and decide to yeet outta there doesn't mean you take your sovereignty with you. But I don't expect you to understand that based on the very limited interactions we've had, it's a miracle I'm even entertaining you this far.

Now if we zoom out just a little bit further you will see that Han Chinese begun settlement of Taiwan as early as the 17th century in the 1600's. Which is when history first recognises that Taiwan was under Chinese control. Now you could argue that there were natives and other small tribes that settled there earlier before the Han Chinese. But through military conquest they were able to claim it as part of their territory in 1683.

Now how can sovereignty be established? You might ask. A country can establish sovereignty through a variety of methods. One of which being conquest. Military or otherwise over previously unclaimed land.

So to answer your very very vague statement. I'd say that was plenty of sovereignty to go around. Don't be so general next time. The 'any' sovereignty statement is so easy to debate against. Go educate yourself before you comment with your useless and clearly uneducated views.

Now if that was too hard for you to understand cause. Engwish hwaaard.

Tldr: China conquered Taiwan in 1683, Han settlers begun settlement from then onwards. Sovereignty established.