Nikolai Rubinstein
When Tchaikovsky's violinist friend Iosif Kotek arrived at Clarens, the composer's efforts quickly became focused on his Violin Concerto, and work on the sonata was discontinued. He resumed work on the sonata in mid-April and completed it before the month's end. It was premiered in a concert of the Russian Musical Society by pianist Nikolai Rubinstein, much to the composer's delight: