In Boston, where he already had contacts through his time at Tanglewood, Mr. Sylvan met the pianist David Breitman, with whom he began a long recital partnership. He also became a part of the prestigious and close-knit ensemble Emmanuel Music, which the conductor Craig Smith had founded there in 1970 at Emmanuel Church, with performances of Bach’s cantatas at the group’s core.
Mr. Smith, who was working on Mr. Sellars’s 1981 production of Handel’s “Orlando” at the American Repertory Theater in Cambridge, Mass., brought Mr. Sylvan in to audition for the title role. Orlando goes mad in an extended, intense, vocally dazzling scene in the second act.
“Sandy’s madness had absolute clarity,” Mr. Sellars said. “No operatic MSG. He put all the big gestures we’re used to from opera into this deeply personal space.”
“Orlando” led to Mr. Sellars’s Mozart cycle and the Adams operas, which became famous for mining recent history for its mythical import. “John found Sandy’s temperature,” Mr. Sellars said, “and Sandy’s temperature deeply inspired John.”
That temperature could seem deceptively mild. Chou En-lai, in “Nixon in China,” is the voice of reason in a tensely charged cast of characters, and Mr. Sylvan projected calm and equanimity. But he also captured undercurrents of fragility and anxiety. His Chou ended the opera in a tone of visionary resignation, summing up the frustration of the Nixon-Mao summit with a single, unanswerable question: “How much of what we did was good?”
While “Nixon” summoned Mr. Sylvan’s gravity and “The Wound-Dresser” his melancholy, “The Death of Klinghoffer” — a reflection on the 1985 hijacking of the cruise ship Achille Lauro by Palestine Liberation Front militants, who killed Leon Klinghoffer, a disabled Jewish American passenger — demanded of Mr. Sylvan an overt outrage not usually associated with him.
But he made Klinghoffer’s indignation musical, and the aria sung by the character’s dead body, falling from the ship after being thrown overboard, was a controlled outpouring, rage focused into tenderness.