The Metropolitan Museum of Art
New-York, US

circa 1360–1380

Full title: Sundial of Ahaz, leaf from the Postilla Litteralis (Literal Commentary) of Nicholas of Lyra

This leaf serves as a splendid exemplar of the medieval diagrammatic tradition, with its graceful fan-like shapes that appear to flutter across the page. Surprisingly, these elements, reminiscent of 20th-century watercolours, are, in reality, abstract sundials employed to illustrate a nuanced aspect of 14th-century biblical exegesis.

Originating from the renowned work of Nicholas of Lyra (1270-1349), Master of Theology at the esteemed University of Paris, this leaf forms a part of his landmark study providing commentary on every book of the Bible. The narrative depicted here, found in both Isaiah (38:1-8) and 2 Kings (20:1-11), recounts a remarkable event where God, as a sign to King Hezekiah of Judea, willingly turned the shadow of the sun back ten degrees — equivalent to about one hour. The illustrations on this leaf present two distinct methods for charting this miraculous reversal of time.