...except that Rome entered into treaty to cede its administration of Iberia to them.
Furthermore, Honorius's grant to Galla Placida could not pass through hereditary succession because neither she nor her husband left any heirs.
Ah, but the Visigothic line did produce an heir after Athaulf's (Adolphus in some translations) assassination - Wallia. Wallia entered into the treaty with Honorius.
Since you have proven eager to hide unpleasant facts in vagaries, you will have to prove the legitimacy of Pelayo's claim.
Your gratuitous insults aside for the moment, Pelagius (or Pelayo in some versions) obtained his legitimacy by visigothic law. He was member of Roderic's court and nobleman of the Asturius province in northern Spain. Pelagius was also one of the only Visigothic noblemen to survive. Visigothic law stated that in an interregnum with no direct heir of the previous monarch, the successor would be selected by a vote on candidates chosen from the remaining nobility, which Pelagius did circa 718 when he began the reconquista.
The grant was given to Galla Placida, who was returned to Rome after Athaulf's death, leaving behind no heirs.
Visigothic law stated that in an interregnum with no direct heir of the previous monarch, the successor would be selected by a vote on candidates chosen from the remaining nobility, which Pelagius did circa 718 when he began the reconquista.
So he proclaimed himself king of a kingdom that had lost most of his territory. Fine.