Opera, or the beginnings of, is thought to have originated with the Greek Tragedies.
As time progressed and music began with lutes, original flutes, etc and songs by Dowland etc emerged, the use of story telling or getting accross the written word through song became more popular.
The use of music in church settings, often without accompaniment also began to take hold in the writing of Gesualdo and his contemporaries.
The first opera to be performed that we know about is considered to be L'orfeo by Monteverdi. Brilliant Opera, but the singing style was much different than today and an art that has all but been lost except by the early music devotees.
From that, the idea of "opera" took hold, hence the beginnings of opera. Basically.
O'Donoghue's Opera was created in 1965.
The Threepenny opera was created from the Beggars opera in 1728. It was written by John Gay, a well known plat writer. It was created from the Beggars opera.
Soap Opera Digest was created in 1975.
Novaya Opera Theatre was created in 1991.
Opera Nazionale Balilla was created in 1926.
Pacific Opera was created in 2003.
The Flying Opera was created in 2008.
The Threepenny Opera was created in 1928.
Germania - opera - was created in 1902.
Fantasio - opera - was created in 1872.
Transformations - opera - was created in 1973.
Gwendoline - opera - was created in 1886.
Satyagraha - opera - was created in 1980.
Chelsea Opera was created in 2004.
Aurora - opera - was created in 1908.
Fortunio - opera - was created in 1907.
Atalanta - opera - was created in 1736.