The modern borders of Brazil extend much further west than the boundary line established by the Treaty of Tordesillas in 1493. Why is that?

by S-Quidmonster
TywinDeVillena

I wrote an answer some time ago that I think covers your question. Feel free to check it out and ask any other questions

https://www.reddit.com/r/AskHistorians/comments/epysm0/comment/femm0e1/