The career of the John Mason, the composer who has left just four surving works, is not easy to trace, because references to two or even three namesakes need to be disentangled. It has generally been assumed that our composer was the John Mason who held a lay-clerkship at Eton College between 1501 and 1506. Recently, however, another - or possibly another - musician named John Mason has been discovered: a singer in the household chapel of Lady Margaret Beaufort, mother of Henry VII. This man was sent to study with the schoolmaster of Tattershall College, Lincolnshire, in 1504, apparently to prepare him for entry into the priesthood; he returned to Margaret's household and said his first mass in 1507. In February 1509 a Dominus John Mason was admitted to the degree of Mus.B. at Oxford, having studied at the university for a year; since the title Dominus (sometimes anglicised as 'Sir') was generally restricted to priests, this is very likely to have been Lady Margaret's newly-ordained singer.
It must surely have been the same Dominus Mason (sic) who served as instructor of the choristers at Magdalen College -- Cardinal Wolsey's old college -- between 1508 and 1510. This Mason now vanishes from sight for more than a decade. When he reappears, in a list of the retinue accompanying Wolsey on an embassy to Calais and Bruges in 1521, he is described as a chaplain of the cardinal's chapel. The date of his appointment to this chaplaincy has yet to be discovered; it could have been several years earlier, perhaps even as early as his disappearance from the Magdalen records in 1510. Between 1521 and 1525 Mason acquired a number of lucrative benefices, including the rectorship of Pewsey, an exceptionally well-paid chantry in Chichester Cathedral and prebends at Salisbury and Hereford. He seems to have settled at Hereford in the mid-1520s and to have spent most of the rest of his life there, apart from a short period in 1529-50 when he came to the assistance of Cardinal College by standing in as a chaplain and master of the choristers following Taverner's resignation. He became treasurer of Hereford Cathedral in 1545; the appointment of a new cathedral treasurer and a new rector at Pewsey early in 1548 suggests that he died during the winter of 1547-8.
The fact that the main source of Mason's four surviving works--the Peterhouse Partbooks--describes him as 'Mason Cicerstensis' ('Mason of Chichester', evidently referring to the chantry mentioned above) might appear to confirm that the musical priest and the composer are one and the same person, were it not for the fact that between 1539 and 1540, when these partbooks were being compiled, this same chantry, which Dominus John Mason had resigned by 1527, was held by a John Mason variously styled 'Mr' or 'Sir'. Which chantrist did the Peterhouse scribe have in mind, or were they the same man? If this discussion seems sterile, it does at least give an idea of the difficulty of identifying people with common names. There is a further piece of evidence that could help to identify the composer: all four of his known compositions are written for male voices only, implying that he was writing for a choir that did not include boy singers.