Once i read in a book ( dont recall the name) that the portuguese strategy in the brazil war of independence was, if not to hold all territory, at least keep the nort of brazil in Portugal hands, because the local elites were in favor to keep under Portugal than Rio de janeiro
I didn't know about that, but it does make sense. The northernmost states were indeed closer to Lisboa than to Rio and answered directly to Lisboa during colonial times. Their delegates to the Portuguese constituent of 1820 were also much more hesitant to abandon the Cortes than the southern delegates.
After Brazil liberated Salvador, the brazilian fleet under britsh admiral Lord Cochrane sailed to the capital of the northern states to demand their submission to the cause of independence.
At São Luis city, one of the most important north cities, after the local governament surrended he sacked the city and returned to England, under the excuse the brazilian governament owend him money and that was the way to get himself paid.
Lord Cochrane died in UK and is burried at Westminster abbey
Well, two centuries later one (in)famous brazilian politician that was our president once, Jose Sarney, who is from São Luis, visited Cochrane tomb at Westminister and cursed him in the name of São Luis people : "Corsair", he said, and spit at his tomb.
Who says this is Jose Sarney himself, as you can see in this article written by him
https://www1.folha.uol.com.br/fsp/opiniao/fz0711200307.htm (portuguese)
Point is, this shows how first relations between Brazil and its north states began, to sack Salvador city was unthinkable, but São Luis was treated as a conquered city.