Tenore di grazia (stylish and graceful)
Nemorino (Donizetti - L'Elisir d'Amore); Tamino (Mozart: The Magic Flute); Ferrando (Mozart: Cosi Fan Tutte); Don Ottavio (Mozart: Don Giovanni); The Duke (Verdi: Rigoletto); Alfredo (Verdi: La Traviata).
Famous tenore di grazia: Ian Bostridge; Bonaventura Bottone; Stuart Burrows; Raul Giménez, Alfredo Kraus.
Lyric and spinto (literally 'pushed', ie vigorous)
Famous roles: Rodolfo (Puccini - La bohème); Radamès (Verdi - Aida); Don José (Bizet - Carmen); Don Alvaro (Verdi - La Forza del Destino).
Famous lyric/spinto tenors: Roberto Alagna; Carlo Bergonzi; José Carreras; Placido Domingo; Beniamino Gigli; Dennis O'Neill; Luciano Pavarotti (pictured).
Robusto and Heldentenor (robust and heroic)
Famous roles: Manrico (Verdi - Il Trovatore) Otello (Verdi - Otello); Parsifal (Wagner - Parsifal); Siegfried (Wagner - Der Ring des Nibelungen); Max (Weber - Der Freischütz); Grimes (Britten - Peter Grimes); Florestan (Beethoven - Fidelio).
Famous tenori robusti/Heldentenors: Enrico Caruso; Franco Corelli; Lauritz Melchior; Alberto Remedios; Jon Vickers; Wolfgang Windgassen.
Some of the confusion over voices types occurs because operatic countries sometimes evolve their own names for particular categories within their own repertoire. For example, in Germany there is a Spieltenor category which is a light, expressive voice required for character parts such as the manservant Pedrillo in Mozart's Die Entführung aus dem Serail and David in Wagner's Die Meistersinger von Nürnberg.
There is also a Hoher Tenor (higher tenor) category which includes Brighella in Strauss's Ariadne auf Naxos and (even more confusingly) the 'Italian tenor' in Strauss' Der Rosenkavalier. France recognises a ténor-bouffe (eg Paris in Offenbach's La Belle Hélène).
Britain has developed its own stable of accomplished character tenors, such as Peter Pears, Robert Tear, Philip Langridge and Anthony Rolfe-Johnson.
These singers have adopted various specialisations - they all sing the leading tenor roles written by Benjamin Britten in his operas, for Peter Pears; Robert Tear has sung in virtually all operatic genres and is a notable Loge (Das Rheingold) and Herod (Salome); Langridge and Rolfe-Johnson are especially accomplished in Mozart and Handel.
All these singers have also had major careers in the concert hall, singing oratorio and the song repertoire.