With virtually all of the most famous American string quartets appearing here in a matter of days this month, it was only suitable that the most venerable and famous of them, the Juilliard, should open its annual Library of Congress season with Beethoven.

It was not, though, just Beethoven. The long and rigorous program, which brought the Coolidge Auditorium audience to its feet at the end last night, was capped by the extraordinary C-Sharp Minor Quartet, that echo of the Ninth Symphony that is a direct antecedent of some of the most complex 20th-century music. And before that on the program was the first of the three "Rasoumowsky" quartets from Beethoven's middle period -- itself, in turn, an antecedent of the C-Sharp Minor.

It would be hard to take any two other quartets from Beethoven's 16 quartets and create a more powerful impression. Beethoven's preoccupation with the implications of death and eternity never reached greater depth than in the slow movement of the first "Rasoumowsky" and in the entirety of the C-Sharp Minor.

They need the greatest intensity from players, as well as the greatest concentration from players and listeners alike. Those two characteristics are the Juilliard's strong points, and that is what the works got last night.

The C-Sharp Minor, which even so normally acerbic an observer as Stravinsky called "perfect, inevitable and inalterable," is as challenging as anything in the repertory. Its seven movements are played without pause, bound together in such a way that they often seem more like a single corpus. This ambivalence between the long line and the episodes provides much of the quartet's sense of expressive desolation and, at times, disorientation.

The long line must never get lost in the multitude of details, and the details must be played with such intensity that the work seems less than overwhelming. Keeping this balance so steadily is what has always made the Juilliard's version of this work seem separate from those of rival ensembles.

Last night, all the strengths of the Juilliard were present here -- tension, rhythmic precision, sharp contrasts and dark timbres. And their most common shortcoming, some roughness of tone, hardly mattered.

The first "Rasoumowsky" is a more conventional work -- what isn't? -- but its powerful last two movements strongly suggest what the ailing Beethoven would write in the C-Sharp Minor 20 years later. If the later work is concerned with the mystery of death, the slow movement of the earlier work is about the sadness of death. It is music of love cast in heartbreaking minor key modes, somewhat like some of the slow movements of the Mahler symphonies. The performance was incomparable.

Before these two quartets there was one of Beethoven's early quartets from Op. 18 -- in this case the Fifth. These works are gracious and relaxed in the 18th-century manner. It is a style that requires more unbending than the Juilliard Quartet can usually accomplish. That was the case last night, splendid as the performance was.