Do not assume that an old piece of music is in the public domain and not subject to copyright.
While the song may be in public domain, the particular arrangement you chose may currently be under copyright and the song will need to be licensed. So pay attention to any notation about arranged by or edited by. Public Domain rules of thumb: Any song or musical work published in 1922 or earlier is in the public domain in the USA. No sound recordings are PD in the USA due to a tangled complexity of federal and state law. Public domain status must be verified separately for each country where the music is used. Music enters the public domain 70 years after the death of the author in most countries other than USA. However, copyright protection may be 95 years from publication date, 50 to 70 years after the death of the last surviving author, or other criteria depending on where the work was first published and how the work is to be used. And one more catch, due to a change in the public domain law (the Sonny Bono Copyright Term Extension Act of 1998 – I kid you not), no new works will enter the public domain until January 1, 2019. Leave it to the government to complicate something so that it needs a chart!