Date of the performance. The English Wikipedia Olimpie discography, citing the booklet of the Opera d'Oro issue (Bill Parker, 2003), gives "Recorded live on 6 June 1966, sung in Italian" for this Molinari-Pradelli/La Scala cast, and Wikipedia's article text dates the Scala revival to 1966. The cast sheet distributed with the tape, in the rip folder as "Olimpie - 1966.06.06 (Molinari-Pradelli, Milan).txt", ends "Milan June 6, 1966" -- month spelled out, so no day/month ambiguity. Adding day and month; year was already right.

Discogs release 25003492, the Opera d'Oro CD issue of this performance (OPD-1395, barcode 723724608924), credits the tenor as Franco Tagliavini alongside Lorengar, Cossotto, Guelfi, Zaccaria and Maionica with the Scala orchestra and chorus under Molinari-Pradelli; the English Wikipedia Olimpie discography, citing the same issue's booklet (Bill Parker, 2003), likewise names Franco Tagliavini. Ferruccio Tagliavini (1913-1995) is a different singer and sang no Cassandre; Franco Tagliavini (1934-2010) also sings the part on the 1984 Albrecht set. Correcting the singer and giving the role the top billing the release prints for it.

Top billing was on Statira, L'Hierophante and Hermas -- two comprimario basses -- while the title role was unbilled. The Opera d'Oro issue of this performance (OPD-1395; Discogs release 25003492) and the English Wikipedia Olimpie discography both print the cast in the order Lorengar, Cossotto, Franco Tagliavini, Guelfi, Maionica/Zaccaria, so the three leads are Olympie, Statira and Cassandre. Olympie is the title character and sings. Billing moved to those three.

Top billing was on Statira, L'Hierophante and Hermas -- two comprimario basses -- while the title role was unbilled. The Opera d'Oro issue of this performance (OPD-1395; Discogs release 25003492) and the English Wikipedia Olimpie discography both print the cast in the order Lorengar, Cossotto, Franco Tagliavini, Guelfi, Maionica/Zaccaria, so the three leads are Olympie, Statira and Cassandre. Unbilling this comprimario role in favour of them; exactly three roles carry noted.

Top billing was on Statira, L'Hierophante and Hermas -- two comprimario basses -- while the title role was unbilled. The Opera d'Oro issue of this performance (OPD-1395; Discogs release 25003492) and the English Wikipedia Olimpie discography both print the cast in the order Lorengar, Cossotto, Franco Tagliavini, Guelfi, Maionica/Zaccaria, so the three leads are Olympie, Statira and Cassandre. Unbilling this comprimario role in favour of them; exactly three roles carry noted.