Gaius Plinius Caecilius Secundus, or Pliny, owes his literary fame to his Letters (Epistulae), which comprise nine books of private letters (books 1-9) and one book of his official correspondence with the emperor Trajan (book 10). Pliny’s epistolary work offers a most valuable insight to the author’s intellectual environment and the culture of literary and political friendship within the Roman aristocracy during Trajan’s dominion. Books 1-9 contain the author’s own collection of 247 private letters addressed to a remarkable number of 105 real, not fictive recipients (Pliny’s friends and other members of the Roman aristocracy of his time). The exact dating of the letters remains unresolved, …
Michalopoulos, Charilaos N.. "Epistulae". The Literary Encyclopedia. First published 03 June 2009; last revised 30 November -1.
[http://www.litencyc.com/php/sworks.php?rec=true&UID=26476, accessed 27 April 2015.]