The original issue was Belvedere (Tudor) ELY 04 30, issued in 1966. It was also reissued on Harmonia Mundi HM 10071 (as noted) and in the US as Nonesuch H 71184. (See Chantdiscography.com). Chants recorded with other versions of the Machaut Mass were sung from MSS or in period style, but this was Solesmes-style chant.
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https://archive.org/details/ely-0430-de-machaut-o-la-messe-de-nostr...
The original issue was Belvedere (Tudor) ELY 04 30, issued in 1966. It was also reissued on Harmonia Mundi HM 10071 (as noted) and in the US as Nonesuch H 71184. (See Chantdiscography.com). Chants recorded with other versions of the Machaut Mass were sung from MSS or in period style, but this was Solesmes-style chant.