As pointed out by José López-Calo and Cristina Diego Pacheco, documents related to the brothers Alonso, Pedro and Rodrigo Ordóñez often do not mention the first name, and thus it is difficult sometimes to ascertain their identity. In E-V 05 there are four polyphonic works attributed to Alonso Ordóñez and one to "Rº Ordóñez"; although the initial in the latter ascription has been interpreted as "Racionero" (to refer to Alonso Ordóñez), it is most likely that it refers to Rodrigo Ordóñez. There are no known works attributed to Pedro Ordóñez.

López-Calo mentions many possible locations that can or could be related to Rodrigo Ordóñez. 

Spanish nobleman, bibliophile and diplomat —ambassador to England between 1613 and 1622—, he collected one of the most important Spanish private libraries of the 17th century; one of his descendants, Marquis of Malpica, donated the library to Carlos III in 1785. Today those books are part of the Real Biblioteca at the Royal Palace in Madrid (E-Mp). Important manuscripts, such as the Cancionero Musical de Palacio (E-Mp II/1335), music printed books and treatises were part of Gondomar's library.