An elegy is a poem that expresses sorrow or lamentation, especially for one that is dead.
Elegies also have love and war as subjects in addition to death.
The term elegy has referred to dignified poems mourning the death of an individual or of all men. Shelley wrote this elegy out of the extreme love and respect he had for Keats, whose death brought on by illness was quickened by horrible and vicious reviews of his poetry. This call to mourning is a typical element of an elegy. No more let life divide what Death can join together.