The Festival Singers assumed professional status in 1968 and became at the same time the core of the Toronto Mendelssohn Choir. Stabilized at 36 voices, they toured Europe in 1971, and again in 1972 with the Toronto Mendelssohn Choir. Further US appearances included concerts at Lincoln Center, New York, 26 Jun 1972, Kennedy Center, Washington, 25 Oct 1976, and the Basilica of Saints Peter and Paul, Philadelphia, 4 Aug 1977. In November 1977 the singers toured in England, West Germany, and the USSR. In Canada they toured the west in 1974 and 1977 and the east in 1975 and appeared at the Stratford Festival during the summers of 1955, 1956, 1958, 1963-7 and 1974, the Guelph Spring Festival 1968, 1973, and 1975-7, the winter seasons of the Shaw Festival at Niagara-on-the-Lake 1973-6, and the Olympics in Montreal in 1976. At Guelph they sang two sections of Penderecki's St Luke Passion under the composer's direction in May 1976. Annual concert series were given in Toronto, and at the height of their fame the singers gave about 25 concerts each year on the CBC.
English and Canadian critics agreed in their estimations: 'The Festival Singers of Canada made a stunning impression... The unanimity of attack was astonishing, the intonation flawless and the tonal balance well-nigh perfect' (London Daily Telegraph, 2 Jun 1971); 'one could not fault the Singers on tonal beauty, ensemble precision or dignity... the Singers swung effortlessly from subtle pianissimos to lusty fortissimos and maintained a delicate balance in even the most complex interweaving of melodic lines' (Toronto Globe and Mail, 1 Jul 1974).
Reflecting Iseler's dedication to Canadian music, the Festival singers commissioned and premiered works by John Beckwith (Jonah 1963), Robert Fleming (Heirs through Hope 1968), Clifford Ford (Mass 1977), Harry Freedman (The Tokaido 1962, Totem and Taboo 1965), the choir's accompanist, 1968-79, Ruth Watson Henderson (Missa brevis 1975), Oskar Morawetz (Two Contrasting Moods 1967), Jean Papineau-Couture (Viole d'amour 1967), Harry Somers (the motet The Crucifixion 1966, Three Songs of New France 1976), Claude Vivier (Journal 1978), Charles Wilson (The Lonely Land 1976), and John Wyre (Utau Kane NoWa 1975, Bernie 1977). The Festival Singers of Canada Choral Series, begun in 1968, edited by Iseler and published by G.V. Thompson, includes several of these commissions. The choir also gave the premieres of Talivaldis Kenins' Lagalaî (1970), Thomas Baker's Chinese Love Lyrics, Wilson's Images Out of Season (1973), Derek Healey's arrangements of Six Canadian Folk Songs (1973), Somers' Kyrie (1974), Norman Symonds' At the Shore (1976), Alexander Brott's Time's Trials Triumph (1977 in Bonn, Germany), David Fanshawe's African Sanctus (revised version, 1978), and several of John Reeves' Motets (1978).
Excepting a period of about a year and a half (late 1960 to early 1962) when ill health forced his temporary resignation, Iseler was the Festival Singers' regular conductor until 1978. In Iseler's absence, Lloyd Bradshaw conducted several concerts, and Walter Susskind and Rowland Pack each conducted one. Iseler himself - as a guest - conducted the final concert in the 1961-2 series prior to returning as artistic director in August 1962, and he retained the position for the ensuing 16 years.
By the mid-1970s there was dissatisfaction about the Festival Singers' objectives and policies among its constituent components - choir members, artistic director, management, and board. Furthermore, concern about the levels and sources of its funding prompted the Canada Council to commission a review of the choir's affairs in 1976. In 1978 these contentious issues resulted in the board announcement on 12 May that Iseler's contract would not be renewed.
Giles Bryant was named music director in June 1978, and Peter McCoppin, Jon Washburn, Brian Law, and John Barnum appeared as guest conductors during the 1978-9 season. The season was not a financial success, due in part to decreased use of the choir by the CBC. The Festival Singers announced suspension of activities in April 1979 and filed an assignment of bankruptcy 30 Jul 1979.
Many solo performers of note, including Mary Lou Fallis, Albert Greer, Ingemar Korjus, Phyllis Mailing, John Martens, Mary Morrison, Patricia Rideout, Freda Antrobus Ridout, Jan Simons, Lillian Smith Weichel, Margaret Stilwell, Eric Tredwell, Alan Woodrow and Gordon Wry were members of the Festival Singers at some time during their careers. The Festival Singers' first governing board came into being in 1968, the year the choir assumed professional status. Board members were enlisted from the music and business communities. Presidents were James Singleton 1968-9, John Bird 1969-71, Gordon Marshall 1971-2, Mrs Thomas H. Thomson 1972-4, Max Holling 1974-6, Ian Woolley 1976-7, Mrs W.D. Heintzman 1977-8, and Charles Tisdall 1978-9.
Beckwith The Trumpets of Summer; Three Blessings. Morrison soprano, Rideout alto, Bartle tenor, A. Gray bar, Iseler conductor. 1969. RCI 340/CBC SM-81/Cap ST-6323/5-ACM 26
Canadian Landscapes, vol 1: Healey - T. Baker - Schafer - Archer. Henderson piano, Iseler conductor. 1974. CBC SM-274/(Schafer) 5-ACM 3/(Archer) 7-ACM 17
Choral Music of Healey Willan. Iseler conductor. 1968. RCI 207/Cap ST-6248/(selections) 5-ACM 11
A Festival of Christmas Music. Iseler conductor. 1956. Hallmark ChS-4
Freedman The Flame Within; The Tokaido. B. Lagacé organ (The Flame Within), Toronto WW Quin (Tokaido), Iseler conductor. 1970. RCI 341/CBC SM-142/Decca DL-75244/6-ACM 8
Joyful Sounds: Schütz - Paynter - Praetorius - Dennis Riley - M. Miller - Hartmann. Canadian Brass, Iseler conductor. 1973. CBC SM-203
Kent Mass No. 1 - Willan Missae breves IV, X, XI. Iseler conductor. 1976. CBC SM-314/(Missa Brevis X) 5-ACM-11
Make We Joy: Holman - Applebaum - Charpentier - Wilson - Kent - Anderson - Ridout - Paul - Mather - K. Jones - Freedman - Beecroft. Iseler conductor. 1973. Poly Medium Stereo 2917-009/(Jones) 5-ACM 24
Make We Merry: Willan - Bach - Paynter - Kirkpatrick - Pearsall. Iseler conductor. 1970. CBC SM-80/RCI-331/RCA LSC-3174
Mundy - Byrd - Gibbons - Lassus - Willan. Iseler conductor. 1955. Hallmark ChS-3
Palestrina - Somers - MacMillan - K. Jones - W. K. Rogers - Kenins - Ridout - et al. Iseler conductor. 1965. CBC SM-19/(Somers) 10-ACM 7/(Kenins) 4-ACM 33 (CD)
Poulenc - Somers - Russell - Beckwith. Iseler conductor. 1967. Cap ST-6258/Sera S-60085
Schoenberg Kol Nidre; Dreimal Tausend Jahre. CBC SO, Craft conductor. 1969. 2-Col M2S-709
- Modern Psalm; De profundis. CBC SO, Craft conductor. 1964. 2-Col M2S-780
- Prelude to the Genesis Suite. CBC SO, Craft conductor. 1962. 2-Col M2S-694
- Survivor from Warsaw. CBC SO, Craft conductor. 1962. 2-Col M2S-679
Somers Five Songs of the Newfoundland Outports. Brough piano, Iseler conductor. 1969. RCI 339/CBC SM-105/RCA LSC-3154/10-ACM 7
- 'Where Do We Stand, Oh Lord?' Iseler conductor. (1980). 10-ACM 7
Straughan Enfilony. Greer Chor Master, Radio-Télé-Luxembourg O, Feldbrill conductor. (1978). Sun Owl SN-001
Stravinsky A Sermon, a Narrative and a Prayer; Anthem; Babel; Zvezdoliki - Bach-Stravinsky Choral Variations on 'Vom Himmel hoch da komm' Ich her'. CBC SO, Stravinsky conductor. 1962. 3-Col MS-6647/22-Sony SX22K-46290 (CD)/(selections) Col M-31124
- Recent Stravinsky Conducted by the Composer. Verrett mezzo, Driscoll tenor, CBC SO. (1967). Col MS-7054/22-Sony SX22K-46290 (CD)
- Stravinsky Conducts Stravinsky: choral selections. 1963. Col M-31124/(selections) 2-CBS M-79255/(selections) 22-Sony SX22K-46290 (CD)
- Symphony of Psalms. CBC SO, Stravinsky conductor. 1963. Col MS-6548/CBS MK-42434 (CD)/22-Sony SX22K-46290 (CD)
We Magnify Thee: Willan - Byrd - Hindemith - Vaughan Williams - Josquin des Prés. Iseler conductor. 1970. CBC SM-179
Kraglund, John. 'Is there a pro choir waiting in wings,' Toronto Globe and Mail, 25 Nov 1967
'Festival Singers of Canada,' CanComp, 49, Apr 1970
'Festival Singers tour Europe - critics call tour ''amazing'',' CanComp, 62, Sep 1971
Roberts, John. 'Stravinsky and the CBC,' CMB, 4, Spring - Summer 1972
Ashworth-Gam, Jean. 'Elmer Iseler and the Festival Singers of Canada: a classic success story,' Recorder, vol 19, Mar 1977
Littler, William. 'Why did Elmer Iseler get the old heave-ho?' Toronto Star, 25 May 1978
Kraglund, John. 'Festival Singers in bankruptcy,' Toronto Globe and Mail, 2 Aug 1979
Hambleton, Ronald. 'Problems that destroyed a choir come to light,' Toronto Star, 8 Aug 1979
Kramer, Marcus R. 'The Festival Singers of Canada: a history,' M MUS thesis, University of Western Ontario 1982