Hi dec-sev,
I sense that you might like some further clarification.
So, we are dealing with a modest historian here
I don't think it's necessarily connected with modesty, although that could play a role in some circumstances.
As pointed out by valvs, "history" can mean either the aggregate (= sum) of past events or a chronological account of them. The former is of course unique, and hence is invariably accompanied by the definite article. The latter is usually (but not always) non-unique, thus necessitating the indefinite article.
Examples:
"The History of Britain" 
(The word "history" is used here to mean "aggregate of [significant] past events".)
"A History of Britain" 
("History" is used here in the sense of "chronological account of past events".)
"An Illustrated History of Britain" 
(Note: the use of the definite article here would not be grammatically incorrect, but would imply that there is only one account of British history with illustrations, which is very unlikely.)
"The Reader's Digest History of Britain" 
(The definite article is reasonable here, because there's probably only one account of British history that is published by Reader's Digest.)
Hope that helps.
Cheers,
Abba