In a message dated 4/11/2000 3:46:08 AM Eastern Daylight Time,
[log in to unmask] writes:

<< At 12:05 PM 4/10/2000 -0400, ditulis John Cowan
 >My favorite Spanish name doublet is Hernan/German, ultimately of Germanic

 I thought Hernán was just an abbreviated form of Hernando, AKA Fernando,
 obviously related to Ferdinand. I remember that in school we learned about
 <Hernando Cortez> whereas every Spanish source I've seen mentioning him
 calls him <Hernán Cortes> (actually I could have the last names mixed up,
 but I know that the spelling used in my textbooks was different from the
 standard Spanish). >>

Seems to me I've seen Cortez~Cortes even in Spanish sources.  Speculation:
Cortez may be formed analogically on the basis of common surname ending -ez
(Martínez, González et al.) applied to given names, originally meaning (I'm
told) "son of". Since "Corte" seems not to be an authorized given name,
perhaps _Cortes_ is a de-accented form of original _cortés_ 'courteous;
courtly'?  I once listed all the -ez surnames I could think of (±30), and
only a handful could not be allied with some Christian name (and even those
few might be based on names no longer in use??)
Then too, there have been occasional unsuccessful attempts at spelling
reforms, and -z in names > -s may be a holdover (like Isabel vs Ysabel,
Ibarra vs. Ybarra).

Hernando/Hernán are simply the Castillian forms of (non-Castillian)
Fernando/Fernán. The husband of Queen Isabela is always referred to as
Fernando--  IIRC he was Aragonese.
Don't know whether (F/H)ernando ~Ferdinand is Germanic or Latinate, but IMHO
it's unlikely to be connected with Germán (Fr. Germain(e); a saint).  Indeed,
that's germanic, a kin-term (cousin?), and survives in Sp. hermano/a, Port.
irmăo, irmă "brother/sister".