Hail, Hail, the Gang's All Here

Hail, Hail, the Gang's All Here is an American popular song first published in 1917. The lyrics were written by D. A. Esrom (pseudonym of Theodora Morse) to a tune originally written by Arthur Sullivan as a spoof of Verdi's Anvil Chorus for the 1879 comic opera The Pirates of Penzance. The tune is part of "With Cat-Like Tread" from Act II of Pirates of Penzance and was modified by Theodora Morse from Sullivan's four-part original.

Today the chorus of the song (with revised lyrics) is perhaps more identifiable (certainly amongst Irish and Scottish communities) as being part of "The Celtic Song", sung by the fans of Glasgow Celtic in Scotland. Glen Daly recorded an "official version" of "The Celtic Song" that is commonly played at Celtic Park prior to matches.

(Original lyrics by William S. Gilbert)

The song is also referred to in Kurt Vonnegut's book, Slaughterhouse-Five:

The door was flung open from inside. Light leaped out through the door, escaped from prison at 186,000 miles per second. Out marched fifty middle-aged Englishmen. They were singing "Hail, Hail, the Gang's All Here" from the Pirates of Penzance.

It appears that the lyric "Hail, hail, the gang's all here" had unofficially been added to Sullivan's melody many years before the publishing of the song. A Philadelphia Inquirer news item from April 1, 1898, for example, stated that during a raucous meeting of the Philadelphia Common Council, council members loudly sang, "Hail, hail, the gang's all here, what the h--- do we care! What the h--- do we care!" Likewise, a Delaware state legislature session in March 1900 was disrupted when Democratic members loudly sang the song. And these lyrics also appear in the closing measures of the 1915 song Alabama Jubilee.

...
Wikipedia