Milton worked for most of his life on a theological treatise that we now know as the De Doctrina Christiana. He probably intended it for publication, but, in the event, perhaps because of its controversial opinions, it remained in manuscript and was forgotten until found in November 1823 in the State Paper Office. Many refused at the time, and some since, to believe it could be Milton’s, so much had he come to be identified as the spokesman for orthodox Protestantism. In the opening introductory Epistle he calls it “my dearest and best possession” (“quibus melius aut pretiosius nihil habeo”) [Milton’s Latin text is to be found in Patterson’s The Columbia Milton (hereafter CM)…
Forsyth, Neil. "De Doctrina Christiana". The Literary Encyclopedia. First published 20 August 2012; last revised 30 November -1.
[http://www.litencyc.com/php/sworks.php?rec=true&UID=5706, accessed 25 April 2015.]