About Antón de Armijo
Cantor and instructor in polyphonic sound. Associated with Francisco Guerrero between 1555 and 1578. He married Maria de Madrid and the two had a son, Ferdinand, born 1565, during his association with Guerrero in Seville. In 1570, he is described as being excused from a reprimand for "inefficiency" as a result of "old age and illness" (he was probably considerably older than age 30 at the time).
From Spanish Cathedral Music in the Golden Age, chapter on Francisco Guerrero:
Sevillian Career (1554-1599) Entries related specifically to Anton de Armijo:
1555, April 22: The (Seville) chapter votes to discount the salary of Anton de Armijo, Francisco Guerrero's colleague in the teaching of polyphony, at the rate of one ducat a month until a debt of 30 ducats is paid. 
1570, May 15 to Nov. 12: Anton de Armijo, Guerrero's deputy during his trip to Santander and Segovia (in the train of Cardinal Gaspar de Zuniga y Avellaneda for the wedding of Princess Anne), annoys the chapter by reason of his inefficiency. However, on June 7, the canons decide to excuse him from a reprimand, because of his "old age and illness." 
1571, Jan. 3: Anton de Armijo is still acting as maestro de capilla during Guerrero's absence. 
1571, Apr. 5: Anton de Armijo borrows 30 ducats from the chapter, to be repaid at one ducat a month. 
1578, July: Armijo, Guerrero's colleague in teaching the choirboys polyphonic singing since 1555, having quit, his post is advertised. 
Mentioned in a biography of Alonso Lobo (1555-1617):
Alonso Lobo de Borja was born on the 25th February 1555 in Osuna, Seville in Spain. At the age of 11, in 1566 he is admitted as a chorister in the choir school at the Cathedral in Seville, where he received his first musical training with Francisco Guerrero (1528-1599), the 'maestro de Seises' (that is master of the "Six boys," a standard number of talented boy singers in the cathedrals and major churches of Spain) as well as with Antón de Armijo (canto órgano, - e.g. harmony, counterpoint-).
From a discussion of the Armijos (Jewish Heritage?):
The furthest relative I can trace on my line is a ANTON DE ARMIJO b. 1540 in Seville, Spain. At age 26 (1566) he worked as a cantor (singer) with Francisco Guerrero (b. 1528 d. 1599) who was a noted Renaissance Composer of SPAIN. They worked together at the Polyphony at THE SEVILLE CATHEDRAL. ANTON DE ARMIJO married MARIA DE MADRID and they had one son, FRANCISCO DE ARMIJO (b. 1565) who was my 10th Great Grandfather.
From a discussion of the Armijos in Seville:
You can also visit the Alcazar de Sevilla, where Anton de Armijo worked in the restoration of the Media Naranja (half orange) a beautiful Moresque ceiling of the palace in 1597 and was the father of Francisco de Armijo, the first Armijo who came to the Americas in 1590.