The mystery eruption of 1452/53 and the omens at the fall of Constantinople

Ice cores hold a big eruption dated 1453 (about 10 million tonnes of sulfur, more than Pinatubo 1991), with far more sulfate in Greenland than Antarctica, so probably in the northern tropics. No volcano has been found. It used to be blamed on Kuwae, but Kuwae is now dated 1458. People have long linked it to the omens seen during the siege of Constantinople in May 1453: a strange Moon, a hailstorm, a day of fog and a light on the dome of Hagia Sophia.

Two questions: (1) do the omens really need a volcano, and (2) can daily records pin down the month the eruption happened, which would help find the volcano.

Where it stands (25 October 2026): sulfur isotopes put the volcano outside the tropics, near or upwind of Greenland (Alaska, Kamchatka, the Kurils, northern Japan or the Cascades are the natural places to look), erupting in 1452 or early 1453. The Smithsonian list has no well-dated eruption of the right size there; the closest dated ones (Aniakchak and Augustine, Alaska, 1540 +/- 100, VEI 4) are too uncertain to test. Of the Constantinople omens only the all-day fog is unusual.