What happened
Several Irish annals – including the Annals of Ulster, the Annals of Tigernach, and the Annals of the Four Masters – contain a brief entry from the 740s: “ships with their crews were seen in the air.” The sources disagree on the year, giving 743, 744, or 748–749. Over time, the terse note grew into a colorful tale. In later versions three ships sailed across the sky, and in others an anchor was lowered from one of them and caught on the church at Clonmacnoise. A sailor supposedly climbed down the rope to free it and nearly “drowned” in the thick earthly air before returning on board. A similar story was also set in England – it is told, among others, by Gervase of Tilbury in his “Otia Imperialia.”
Witnesses
Unnamed people gathered at an assembly and, according to the later legend, the monks of Clonmacnoise. The account survives in annals compiled in monasteries.
Explanations and hypotheses
Historians treat the elaborate versions as a legend that accumulated details in the hands of medieval authors. Several explanations have been proposed for the original entry: ship-shaped clouds, the aurora borealis, and – most often in recent work – a superior mirage, which can show distant ships high above the horizon. Ufologists see it as one of the oldest accounts of a flying ship.
Disputed A likely explanation exists, but some of the facts are still disputed.
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