The Last Rose Of Summer 

André Rieu Live at the Point, Dublin, Ireland.
The Last Rose of Summer is a poem by Irish poet Thomas Moore, who was a friend of Byron and Shelley. Moore wrote it in 1805 while at Jenkinstown Park in County Kilkenny, Ireland. Sir John Stevenson set the poem to its beautiful melody and it was published in a collection of Moore's work called Irish Melodies (1807-34). It was made popular in the twenty first century in a recording by Charlotte Church and the Irish Tenors.
This melody was used extensively throughout Friedrich von Flotow's opera "Martha," first performed in 1847 in Vienna. According to the Grove Dictionary of Music and Musicians (1954), this opera was a remodelling from a ballet written in conjunction with Burgmuller and Deldevez and produced in Paris in 1844 as "Lady Henriette." It stands to reason, based on the evidence, that Flotow made liberal use of Stevenson's melody.
It is sung in the Musical group Celtic Woman by Méav Ní Mhaolchatha and Hayley Westenra