[MR] Oldest English Horary Quadrant Up For Auction

Garth Groff and Sally Sanford mallardlodge1000 at gmail.com
Tue Dec 12 02:14:22 PST 2023

Noble Friends,

What is a horary quadrant, you ask? Well it is an amazing piece of medieval
technology, perhaps you could say the first cousin to an astrolabe. A
horary quadrant could be used to calculate the height of an object,
including the sun in relation to the horizon. With tables it could be used
to calculate the proper date for Easter Sunday. It also included a portable

Quadrants of different types date to antiquity. They are mentioned in the
Rig Veda, which dates to perhaps 1500 BCE. The horary quadrant probably
dates to about the 9th century, and may have been invented in Baghdad.
Leave it to the ingenious Arabs to come up with this useful tool. They were
far ahead of medieval Europe in science, and would remain so for several

Only a few such horaries survive, and this one will be auctioned by
Christie's on Wednesday. It bears a 1311 date, making it the oldest horary
known in England. It is expected to fetch an . . . uh . . . astronomical

The object can be seen at https://www.thehistoryblog.com/archives/68997 .

More about the horary, and related quadrant instruments is found at
https://en.wikipedia.org/wiki/Quadrant_(instrument) .

Yours Aye,

Mungo Napier, Laird of Mallard Lodge  🦆
Continuing a quest to keep Merry Rose relevant and in business.

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