The only unnumbered one of these works is based on a poem by Byron.
The first movement of an unfinished work of this type by this composer was reworked into the composer's third piano concerto, and its later movements were reworked into the Andante and Finale by Sergei Taneyev. The finale of one of these works by this composer includes a theme based on the folk song "In the Field Stood a Birch Tree." The second movement of the first of these works is called "Land of Desolation, Land of Mists." The only unnumbered one of these works is based on a poem by Byron. A bassoon solo marked with six ps appears in the sixth one, which ends with an Adagio lamentoso fourth movement. For 10 points, name these works by a Russian composer, which include ones nicknamed Manfred and Pathétique.
The first movement of an unfinished work of this type by this composer was reworked into the composer's third piano concerto, and its later movements were reworked into the Andante and Finale by Sergei Taneyev.
symphonies by Peter Ilyich Tchaikovsky [prompt on partial answers]