(Also, if you'd like, we could create an unusual/strange names thread, I certainly have some gems I've found during my years of genealogical and (super)centenarian research, from the pre-strict naming laws era.)

Hahaha, you're welcome.
I think a thread for unusual names could definitely be created—it’s a really interesting topic. There are some very unique names out there that I’d love to know about.

(Also, if you'd like, we could create an unusual/strange names thread, I certainly have some gems I've found during my years of genealogical and (super)centenarian research, from the pre-strict naming laws era.)

nomes estranhos (lagoasanta.com.br)

I've always found it so interesting how you (a generalised "you", I mean) there in Brazil kept the archaic spellings of so many names and surnames ("Manoel" instead of Manuel", "Souza" instead of "Sousa", etc.). Over here, the archaic form "Manoel" is no longer in use.

You're absolutely right about that; in fact, many people here consider "Manuel" archaic and think "Manoel" is the more correct spelling.
These spelling differences are often due to the clerks, as many make mistakes when writing down the name.
In some cases, however, parents simply prefer one form over the other and specifically request that spelling.

And yes, there's the "chain of namesakes" effect undoubtedly at play too, I was actually going to point that out in my earlier post but forgot (great minds think alike 😉). Like you said, you could have a son named after his father, who would then give a son of his own the same name, etc. (for instance, there's a branch of my family where four consecutive generations of male ancestors had the exact same full name, their shared given name happened to be Manuel), or something like a grandparent's name being given to several of their grandchildren, or a godparent's name given to several godchildren of theirs, and these younger individuals would then have descendants/godchildren named after *them* in turn, making the name in question more common, like you said.

@diego I do believe your idea regarding King Manuel I (D. Manuel I) might be more likely (or might have become more likely over time, even the name originally started becoming popular due to the biblical name Emmanuel). However, it is worth noting that the given name "Emanuel" also exists in Portugal, though it is *much* rarer than Manuel (incidentally, Emanuel was my maternal grandfather's second given name). One often finds significant regional differences regarding popular Portuguese names in old records and in the modern day, so I do find it unsurprising there is this interesting difference between Brazilian and Portuguese naming customs (even if, as you pointed out, many of the popular male names were/are the same).

That is exactly what happens here too; we do have "Emanuel," but "Manoel" and "Manuel" are much more common—perhaps because the contracted form became more popular over time as the Portuguese version of the Latin "Emmanuel."

Regarding the names that are very common, I also believe there is another explanation: in the past, parents gave their own names to their children. Since these were already common names, at least one child would inherit the same name; consequently, the name was perpetuated through the family line and became increasingly common. If it were a religious family, the likelihood of using common religious names would be even higher.
But these are just thoughts—nothing certain.

João, José, Antonio, Pedro, Francisco, and Joaquim—I believe the explanation is religious; these are important biblical names, and Portugal has a very large Catholic population, just like Brazil, where these names are also very common.
However, Manuel is not.
Although one possible explanation is that the name derives from Emanuel—which *is* biblical.
It could also be a tribute to King Manuel I, a very important figure in Portuguese history who funded the 1498 voyages to establish the sea route to India, as well as the expedition that led to the discovery of Brazil.