Short answers, pulled from the story.
The trombone is the only brass instrument capable of producing a true glissando, a smooth slide from one pitch to another without interrupting the airflow. This feature has defined its unique voice since the 15th century.
The instrument's history begins in the Renaissance, where it was known as the sackbut. This name is derived from the Italian word for trumpet combined with a suffix meaning large.
Christoph Willibald Gluck was the first major composer to use the trombone in an opera overture with his 1767 work Alceste. He subsequently used the instrument in Orfeo ed Euridice and Iphigénie en Tauride.
The tenor trombone has a fundamental note of B and is usually treated as a non-transposing instrument. Tenor trombones with C as their fundamental note were almost equally popular in the mid-19th century in Britain and France.
Plastic instruments including the pBone and the Tromba plastic trombone emerged in the 2010s as a cheaper and more robust alternative to brass. These instruments have found increasing popularity as practice tools that make for more convenient travel.