Performing and recording the complete set of Beethoven’s sonatas for fortepiano and violin had been a dream of ours for years. They constitute a cornerstone of the repertoire, and we knew—from our years of experience with earlier music and our study of the historical sources—that historical instruments, and the historical playing techniques that go with them, would shed new light on these masterpieces. Performances of these pieces on historical instruments are rare. There are serious obstacles to performing them in concert: you need top-notch fortepianos, and an intimate but vibrant chamber-music performance space. And the pieces, difficult in any case, are even more so on period instruments; modern instruments are far more forgiving.