The following curious ballad, which is by far the earliest yet discovered on this subject, was first pointed out by Mr. Wright, in a manuscript of the time of Henry VI. in the library of Trinity College, Cambridge, R. iii. 19. The key to the subject of it may be found in a singular letter printed in Sir Henry Ellis's Original Letters, Second Series, vol. i. p. 110, from which it appears that ships were every year fitted out from different ports, with cargoes of pilgrims, to the shrine of St. James of Compostella; for, strange as it may seem, pilgrims at this time were really, as Sir Henry Ellis observes, articles of exportation.” [Early English Poetry, Ballads and Pop. Lit, Early Naval Ballads, Halliwell, 1841, pp.3-4]
Note: Too many footnotes to transcribe here. Lyrics are a repeat.