I know this opera from the terrific performance that Vittorio Negri conducted of it for Philips back in 1978, which was my introduction to Vivaldi as the greatest of all Italian composers of opera. That LP set stunned me, because all of the books on music said that Vivaldi was important only as an orchestral composer, and this opera is greater than any of his orchestral music; it showed me what I subsequently learned from purchasing recordings of 16 more of his operas plus all of his sacred choral music -- that Vivaldi's inspiration when composing for the human voice exceeded by far his inspiration when composing only for instruments. This opera made me aware that Vivaldi was a very great composer.
One of Vivaldi's least great operas, Arsilda (disappointing because of its being dominated by recitatives), received a terrific performance by conductor Federico Maria Sardelli, and his Modo Antiquo orchestra, and so I look forward to purchasing their performance of Tito Manlio, when the price on it comes down.
Tito Manlio is, along with Farnace (of which there is unfortunately no good performance yet on CD), and Ercule (which received a superb performance from Fabio Biondi) one of Vivaldi's three best operas that I have heard. Tito Manlio is the most stately of those three super operas, and also the longest, but it isn't as radiant as Ercule, nor as architecturally magnificent as Farnace.
Sardelli is a major conductor, as was Vittorio Negri, and I look forward to finding out whether Sardelli does as terrific a job with Tito Manlio as Negri did. I hope that Philips will re-issue Negri's Vivaldi performances on CD.
It is not normally my practice to rate a CD recording that I have not yet heard, but I make an exception in the present instance, because no one else has reviewed this set, and because certainly Tito Manlio is one of the greatest operas ever composed, and the conductor and orchestra on this set are also terrific, and I think that people should know how fine both the opera and its performers are. (As for the soloists on this set, the ones I know are excellent.) Perhaps this review should be removed after a few others appear from individuals who have heard this particular set.