Lets hear what you got from this, Portgas wasnt mentioned but Ace was in this chapter.
I'll give you a short summary, but I could actually write pages about these connections.
One Piece is heavily inspired by Era of Maritime Discoveries, and that should come as no surprise, because it's a manga about piracy and seafare.
Portugal is a really small country, but it was actually the first transcontinental Thalassocracy/Empire of the Sea, closely followed by Castile (Spain). Those two countries actually signed a treaty called Tratado de Tordesillas, that divided the world in two explorable regions, to end disputes between the Kingdoms. Portugal could explore the eastern world (Africa + Asia), and there are some mentions of it actually being called "Paraíso", and Spain could explore the western world (Americas), called the "New World" and that's pretty much what the Red Line symbolizes.
We have good guys and bad guys on both sides, but let's put it like this: D. is probably derived from Dom/Don, The usage of Dom was a prerogative of princes of royal blood and also of other individuals to
whom it had been granted by the sovereign.
The Celestial Dragons seem more spanish oriented so far, with Jay Garcia and Donquixote.
Ace on the other hand, comes from the Portgas+Gol = Portugol/Portugal bloodline. It could also be that Portgas is the portuguese half, Gol is the spanish half, and he's the messianic figure supposed to change the world, because he unites both halves.
This chapter didn't give me the Portgas name I was looking for, but it pretty much sealed the deal: Ace could jokingly bestow the D. name upon Sabo, because he's the rightful monarch.
There are two really cool twists regarding Luffy and Sabo, and why it doesn't really matter, but it would get really long and this is not the right thread.
I hope you enjoyed reading this!
Edit: I forgot about the Marshall and Mary Geoise parts, because I had to provide context first, but if you found this interesting and want to hear more about it, pm me and I'll share my conjecture on those.
