From The Nun's Dark Ages flashback to Ed and Lorraine Warren's last paranormal investigations, the timeline for the Conjuring Universe includes a mixture of authentic historical events, fabricated truths, and wholly original ideas. The Conjuring's timeline is littered in sacrilege, seances, and the supernatural, and though most of the entries in the Conjuring franchise can work as standalone stories, they're all meticulously threaded together courtesy of demonic links that take the form of porcelain dolls, nuns, and even a vintage tin zoetrope.
https://screenrant.com/conjuring-universe-complete-timeline-nun-warrens/