So I was in Early Modern History class the other day, and we we're talking about the attack on Malacca by the Portuguese, led by Alfonso de Albuquerque. While I didn't think too much of it at first, it quickly came to my realization that this was a weird historical figure for a city located in New Mexico to share a name with. After a quick wiki search, I found out that the city was apparently named AlbuRquerque at first, after a Spanish duke, but the R quickly got dropped. So my question, more specifically i guess, is when did this change occurred exactly, and could have it been intentional ? Also, were there any consequences of such a change, or was the rivalry between Spain and Portugal already sort of irrelevant when it happened ? Thank you in advance :D !
Iberian Alburquerque is a town very close to the present border between Spain and Portugal. Catholic settlement in the area is attested around 1200, but it is likely that an islamic population was present in the area. The word Alburquerque may have its origins either in Albus Quercus (latin for white oak) or in Abu-al-Qurq (arab for country of oaks, in any case possibly refering to cork oaks - Quercus Suber). The town was at a time direct property of the portuguese king, Sancho I, who gave it to a bastard daughter in or around 1210 as dowry for a wedding with a spanish noble. In Portugal, this is the "canon" origin for the surname "de Albuquerque" - a toponimic. And Afonso's, the explorer, genealogy can be traced to this family. He was not, however, lord of Albuquerque, the town with a castle, as we shall see...
However, toponimics are very common during this period, and "de Albuquerque" must have also evolved into a surname in other families who migrated from there. Migration from there was probably a common event in the 14th / 15th centuries. The region was contested between Portugal and Spain, peripheric by then, and ravaged rather frequently. A lot of surnames based on toponimy are reasonably frequent in both portuguese and spanish, so that people don't associate them with a particular country or a particular person or even a particular place.
By the middle 15th century, however, Alburquerque (Spanish form has an extra r, portuguese form at the time was Alboquerque) was under spanish (castillian) control. The first line of masters of Albuquerque had died out in 1365, in the heat of internal strife in Castille, and King Peter of Castille had incorporated all their lands into the Castillian crown. This original family had strong ties with portuguese monarchy, but also castillian blood. Although the land was incorporated into the castillian crown, several de Alburquerque carried the name on both sides of the border. In 1464 (when Afonso, the explorer, was around 10 years old), Henry the IV of Castille created the duchy of Alburquerque, for a great noble of his house, Beltran de la Cueva. Alburquerque wasn't the center of a landed title for a century by then. This man, the first duke of Alburquerque died in 1492, a well-recognizable date, and 200 years before the founding of modern Albuquerque, NM. He left a big mark in spanish history. The lineage continued and there were many dukes of Alburquerque in spanish history (lineage is still alive and now in the 19th duke). There wouldn't be confusion, at the time, about which Alburquerques were being honored.
So this answers your "main question", although I suspect you found some of it already. As to the drop in the "r", your specific question, sorry, I have no idea, my wild guess goes for anglicization of the word.
EDIT: (added some extra information about how the first house of Alburquerque ended, and some clarification on a few sentences)