This figure is from an illustration at the beginning of Euclid’s Elementa, in the translation attributed to Adelard of Bath.
Description: Detail of a scene in the bowl of the letter ‘P’ with a woman with a set-square and dividers; using a compass to measure distances on a diagram. In her left hand she holds a square, an implement for testing or drawing right angles. She is watched by a group of students. In the Middle Ages, it is unusual to see women represented as teachers, in particular when the students appear to be monks. She may be the personification of Geometry.
Source: The British Library (via Wikimedia Commons); Date: 1309 – 1316, France (Paris); Copyright: Public domain