1‭ May 664 AD: A Solar Eclipse was observed  in Ireland on this day. 

Darkness on the Kalends of May at the ninth hour

Chronicum Scotorum

Darkness on the kalends of May‭  at the ninth hour and in the same summer the sky seemed to be on fire.

‭Annals of Ulster

‭This was also how this astronomical event was recorded in the Annals of Ulster and the Annals of the Four Masters amongst others

‭The eclipse was witnessed by peoples across the Northern hemisphere from central Mexico, along the eastern seaboard of North America, over Newfoundland then across the Atlantic to been seen over the north of Ireland, the Scottish/English borderlands and then into Germany, Poland and the Ukraine.

Using modern astronomical methodology it is possible to track back in time and pinpoint the time and trajectory of  how the event would have been witnessed in these islands to show that a full solar eclipse was seen here @ 16.50 on that day.

The Solar Eclipse would have been seen as a portent of bad tidings

- and as it turned out in that summer the Plague appeared in Ireland and ravaged the Country.

The plague reached Ireland on the Kalends of August.

Annals of Ulster

Map: NASA - Total Solar Eclipse of 664 May 01