What type of document is this? How do you know this?
The document also referred to as the Veritable Records of the Ming is the collection of imperial records of Ming dynasty emperors (1368-1644). It is single largest and most important source of the history of dynasty which provided the foundation for historical reconstruction of Ming dynasty and its politics, culture and society. I came know about it when I was studying Chinese history.
When was this document written?
The document was written during the rule of Ming dynasty i.e., during 1368-1644 A.D.