The ophicleide takes it's name from the Greek words for serpent (‘ophis’) and stopper (‘kleis’). This perfectly sums up the instrument - a type of metal serpent with keys. Patented by the French maker Halary in 1821 the instrument took over much of the role of the earlier serpent with many composers such as Berlioz, Mendelssohn, Schumann, Verdi and Wagner writing for the instrument.
The idea of keyed brass instruments was not a new one. Trumpets and bugles had had keys added to them as early as 1770. Haydn famously wrote for the keyed trumpet in his trumpet concerto written for keyed trumpet player Anton Weidinger.