Dido's aria, "When I am laid in earth" is from Act 3 of the opera Dido and Aeneas by Henry Purcell composed around 1688.
The words are
When I am laid, am laid in earth, May my wrongs create
No trouble, no trouble in thy breast;
Remember me, remember me, but ah! forget my fate.
Remember me, but ah! forget my fate.
Here is an arrangement for solo cello and string orchestra
The PDF contains the score and all parts.