The late fifteenth-century Pepys and Ritson manuscripts are very much smaller and less elaborate than Eton, Lambeth and Caius; they contain shorter and rather simpler pieces, presumably for smaller and less able choirs, for whom works such as the Eton antiphons and Magnificats would have been beyond their ability.
The Pepys MS is so-called because it was numbered among the diarist's books; he described it as containing 'monkish music of Edward IV's time.'
Although Pepys associated his MS with the reign of Edward IV (1461-1483) the book was probably begun a year or two earlier on internal evidence. The MS was probably completed some time after 1465, because it refers to the composer Hawte as 'Knight' and 'Sir William Hawte', and he was knighted in that year.
The Ritson MS, unlike the Pepys, was on internal evidence the work of at least five distinct hands. It was compiled over a long period between early in the second half of the fifteenth century and 1510, apparently in the West Country.