Non-fiction is the form of any narrative
A narrative is a constructive format that describes a sequence of non-fictional or fictional events. The word derives from the Latin verb narrare, "to recount", and is related to the adjective gnarus, "knowing" or "skilled"...

, account
A report is a textual work made with the specific intention of relaying information or recounting certain events in a widely presentable form....

, or other communicative work whose assertions and descriptions are understood to be fact
A fact is something that has really occurred or is actually the case. The usual test for a statement of fact is verifiability, that is whether it can be shown to correspond to experience. Standard reference works are often used to check facts...

. This presentation may be accurate or not—that is, it can give either a true or a false account of the subject in question—however, it is generally assumed that authors of such accounts believe them to be truthful at the time of their composition or, at least, pose them to their audience as historical
History is the discovery, collection, organization, and presentation of information about past events. History can also mean the period of time after writing was invented. Scholars who write about history are called historians...

ly or empirical
The word empirical denotes information gained by means of observation or experimentation. Empirical data are data produced by an experiment or observation....

ly true.