Alfonso
A Spanish and Italian surname from the given name Alfonso, originally meaning “noble and ready.”
The #2,927 most common surname in the United States (2010 Census) — about 1 in every 25,212 Americans shares it.
Etymology
Alfonso is a surname taken from the medieval personal name Alfonso. That given name ultimately comes from a Germanic compound usually explained as meaning something like “noble” and “ready” or “eager,” though the exact early form is debated. In Iberia the name became very popular because of kings and nobles named Alfonso, and surnames were later formed from it in the usual patronymic way.
History
The name was borne by several medieval kings of León, Castile, and Aragon, which helped spread it widely across Spain and into Spanish-speaking communities elsewhere. As a surname, it is most common in the Spanish and Italian worlds, and it may also appear among families of Hispanic origin outside Europe. The historical excerpts you provided mainly show Alfonso as a royal name, not as a surname entry in itself.
Origin
Regions
Variant spellings
Fun fact
Because Alfonso was such a prestigious royal name, it often spread through baptismal naming long before it became a hereditary surname.
From the historical record
“SANTIAGO IMP. LAS ARTES MECANICAS, SAN ALFONSO 47 1907”
— Diccionario de los apellidos