Orchestral music featuring the timpani

Of all the Baroque-era composers, it was Bach who made the most inventive use of the timpani by weaving it into his works. The "Christmas Oratorio", written to commemorate the birth of Christ, the grandest festival held by Christians, features some of Bach's most brilliant timpani passages.
The singing that expresses the joy of the birth of Christ can be heard in the choral song that begins the Oratorio, but timpani parts are used in the introduction of that song that are suggestive of this joyful occasion.

Original score for the Ninth Symphony

Original score for the Ninth Symphony "Choral"

In the era of the Classicist composers, Beethoven was famous for his clever use of timpani. His idea of tuning to a variety of keys while using just two instruments led to surprisingly impressive results. A good example of this would certainly be the second movement of his Ninth Symphony, "Scherzo".
The two timpani used in this movement are tuning to F one octave apart, with the timpani playing a solo role. This method was used in his previous work, the Eighth Symphony, fourth movement, but it was aggressively hammered out in the main theme of the Ninth, making the timpani an affirmative part of the music. Beethoven's superlative use of timpani has been praised even by one of the masters of orchestration, Berlioz.

Berlioz also added many new ideas to the world of timpani performance, having lauded Beethoven's use of timpani in his works. His "Symphonie fantastique" with its famously lavish orchestration made use of four timpani at the end of the third movement, "Sc?ne aux champs," to cleverly simulate the sound of rolling thunder from afar. In other parts of this work, he gives detailed specifications for different mallet hardnesses and performance techniques on his written score.

Hector Berlioz

Hector Berlioz

Mahler's legacy of a giant symphony with a giant orchestra featured surprising use of the timpani. Symphony No. 2 is famous for its use of three timpanists.
One of the remarkable characteristics of this piece is the use of the exceptionally low note "Des" (D-flat). As for Mahler's other pieces, in his Symphony No. 4 and Symphony No. 8 (the latter called "Symphony of a Thousand"), he directs the timpanist to use two mallets to play a single timpani, producing a powerful sound; and in Symphony No. 1 ("Titan"), he instructs one timpanist to do a glissando using a timpani tuned a half step lower, while the other timpanist plays. It is surprising that these creative ideas from Mahler were executed with the older screw timpani in mind, rather than pedal timpani.