The first entry is always the pin's source. Overall confidence is a weighted average of how firmly each reference supports the start and end times used above; a reference counts half as much for every 180 days older than the newest.
The sources agree on the month, not the day: the plague ships are recorded as reaching Messina in October 1347, so the pin covers that month rather than claiming a date.
The WHO's standing account of the disease, its three forms and its persistence today.
Something missing or wrong? Say it in your own words: a link that backs this pin up, a different start or end date and why, or a fact it lacks or gets wrong. The AI checks it against this pin's sources, searches for better ones, and adds any page that backs you up. The pin's own sources still count most.