A particularly ornate copy of the first three books of Euclid’s Elements was produced in Italy in about 1510 (Plimpton MS 214). The title as given on the first page of text is shown below.
Folios 3v-4 provide some basic definitions.
The circle and its properties are studied on folios 95v-96.
An anonymous Italian Euclid from 1541, first folio:
Some sample folia:
The top three images have been obtained through the kind cooperation of the Rare Book and Manuscript Library of the Columbia University Libraries; the others are from the UC Berkeley Library. These and more images may be accessed via Digital Scriptorium, a digital collection of medieval and early Renaissance manuscripts made available by a consortium of cooperating university libraries headed by the University of California, Berkeley.