This looks like it’s going to be a lengthy post so I apologize in advance bit this particular piece has a lot of history!
The chasuble in it’s original form was perfectly round with a hole cut in the center for the head to go through. The name is said to be derived from the Latin word casula which means little house. A good translation in my opinion since I think of my circular cloak as a small tent. Moving on. There’s a mosiac of Pope Honorius who died in 638 A.D. in the Church od St. Agnese at Rome which depicts him vested in a chasuble that touches the ground all around him. This version of the garment effectively covers his entire figure. During the following centuries the garment became shorter and eventually it was clipped and altered so that there was a considerable diversity in the make of it. I’ve included a photo to the left of varying styles.
Figure 29 in the photo (the one in the center) is a measured drawing from an extant extant example in the V&A museum. (No. 8359 of 1863) I tried to find the image within the V&A collections but there was no image attached to the file. Boo. This particular model is seamed at the shoulders to fit the pattern (it is made of a striped silk). The chausable in the figure was measured at 59 inches in length and 48 inches in width.* It has been deduced that the cut of the chasuble changed due to its weight. Some of them were heavily embroidered like the one to the right and so got quite heavy. Less material over the arms allowed movement and lightened the burden on the poor man wearing it!
*Mary G. Houston, Medieval Costume in England and France: The 13th, 14th and 15th Centuries (New York: Dover, 1996) 24.