Since its first publication nearly ninety years ago the early Tudor Mass O quam suavis has been celebrated as a tour de force of enigmatic notation. The setting of Ave regina celorum preceding the Mass in the unique source is notationally even more recondite, and no convincing edition of it appears previously to have been published. The two works are here deciphered and presented in accessible performing editions, together with a study of their background, purpose and composer. For four and five voices: (S)ATBarB. xviii + 69 pages. ISMN 979 0 57039 181 3.