I am using Evernote for historical research. The materials I am writing about have dates of their own, that are unrelated to the date that I create or update my notes. To keep the historical timeline in order, it would be helpful to have a special user-created (and always user-revisable) date tag that the notes could then be sorted by.
For example: In January 2017 I add a note about the Civil War. In April 2017, I add a note about the Revolutionary War. In September 2017, I add a note about WW2. I then update the Revolutionary War note December 2017. If I sort by date created, the notes