Let me get this clarified: I believe that the husband of a Spanish princess was created into an Infante of Spain by GRACE if he met the following conditions --

1) He himself was a born prince
2) He settled permanently in his wife's native land

As it was, both daughters of King Alfonso XII married men who qualified (Prince Carlo of Bourbon-Two Sicilies and Prince Ferdinand of Bavaria). Accordingly, both were granted the title Infante of Spain (but not the style of Royal Highness, since they already had that). Both Infantas (Maria de las Mercedes and Maria Teresa) retained their succession rights and transmitted them to their children.

Is this correct? What about PORTUGAL? Did the same rules apply there? Was there such a thing as a Portuguese Infante by Grace?