Letter to Hermarchus
From Epicurus Wiki
The Letter to Hermarchus is extant letter of Epicurus written at the very end of his life. It is preserved by Cicero in De Finibus II.30.96:
Epicurus to Hermarchus, greeting. I write these words on the happiest, and the last, day of my life. I am suffering from diseases of the bladder and intestines, which are of the utmost possible severity. Yet all my sufferings are counterbalanced by the joy which I derive from remembering my theories and discoveries. I charge you, by the devotion which from your youth up you have displayed towards myself and towards philosophy, to protect the children of Metrodorus.
See also: Letter from his last days