Written sources are usually categorized in three ways:
Narrative or literary
diplomatic or juridical
socialdocuments
chronicles or tracts presented in narrative form, written to impart a message whose motives for their composition vary widely.
Narrative or literature
are understood to be those which document/record an existing legal situation or create a new one, and it is these kinds of sources that professional historians once treated as the purest, the "best" source.
Diplomaticsources
The classic diplomatic source is the charter, which a legal instrument.
is usually sealed or authenticated to provide evidence that a legal transaction has been completed and can be used as evidence in a judicial proceeding in case of dispute
LegalDocument
are information pertaining to economic, social, political, or judicial significance.