The consolatio ad Helviam matrem was supposedly written in the mid-42 AD, maybe 10 months after the exile imposed on Seneca from Claudius (Letta 1998, 51 ff.). The work is dedicated to the mother of the philosopher, Helvia, who suffers for the relegation of the son in Corsica.
The main witness of the text is the codex Ambrosianus C, 90 inf. (commonly referred to as ‘A’), which contains, in twelve books, all the Dialogi written by the author. The Consolatio ad Helviam is transmitted in the twelfth position, but it has probably been composed 18 months later than the Consolatio ad Polybium (Ferril 1966, 254 and n. 4), in which Seneca, under the pretext of consoling a powerful freedman …
Li Causi, Pietro. "De Consolatione ad Helviam matrem". The Literary Encyclopedia. First published 03 July 2015
[https://www.litencyc.com/php/sworks.php?rec=true&UID=35643, accessed 22 February 2019.]