The salmon returns to the river of its birth

Time to return to Lisbon. I have a ticket for a KLM flight to Lisbon on 1st March; I exchanged it against a voucher they gave me as compensation for a flight that had been cancelled at the beginning of the Plague. And I have projects. A research project concerning Adamic restitution, and more than this. I'm thinking about writing a book in English, a thick book, a synthesis of all what I learned about Portugal during those years, and of what I wrote about Portugal in Polish. I even have a title: "Empire and Nostalgia. A History of Portuguese Culture". It sounds like the title of my old book in 2015 ("Imperium i nostalgia"...), so I would probably have to change it later on, but it serves me for now. But I will keep the structure (something and something). I am currently reading a similar book, The Icon and the Axe, by James H. Billington, a 1966 history of Russian culture. It inspires me; it reads so well, it is still so insightful. I like books that age well. 
This is why I would like to write something similar about Portugal, over some 500 dense pages. I think it's feasible, after Mgławica Pessoa, and after all those former books, like Terytorium a świat. Alternatively, I also think about a book that would deal exclusively with Portuguese Renaissance, a long Renaissance that would stretch till the end of António Vieira's life, and the evacuation of Mazagao. With all those adventures around the globe, including missions in China and in Japan, it might also fill 500 dense pages. 
Which of the two? I don't need to decide right now, I could just open a new file, and start extracting and translating into English whatever was worth having in my old Terytorium. I still have two boxes of notes I made at the time I was working on that book.
Something and Something. A History of Early-Modern Portuguese Culture.