I got a little sidetracked today while looking for images of 14th century clothing - because, well, of the question of lacing.
There is one image from a South Tyrolean mural, dated 1360, where in two cases, the tight-fitting woman's dress is clearly showing lacing in the front. This, in turn, is tied to the garment having a cut in quarters (with a divided front into two panels, or else the front lacing does not make any sense at all). Most of the other images of women I can find from the later half of the 14th century do show tight-fitting dresses, sometimes with a strongly accentuated bust, but there's no lacing or other closure shown.
The fit of the dresses (especially the accentuated bust, and these dresses often have a very wide neck-opening) does point towards there being some kind of fitting that requires an opening; or it was a wool dress that could be stretched over the rather squishy bust. In that case, the breasts would either need to be naturally shapely and firm, or an underdress would have to do any shaping required, as a wool dress will stretch nicely, but not necessarily so with a linen lining.
Which brings us to the many, many questions. A tight-fitting dress does need to have some substance on the tight-fitting areas, which points toward there being a lining; in that case, it can also do some shaping. This means an opening is required. So... when do the first images with a front lacing on a woman's dress turn up?
I'm happy for any hints towards this! I can offer, as linked to above, 1360 as the starting point, located to South Tyrol; I have a nice side lacing from the 1320s, and another front lacing from England, 1370-75.
The hunt is on ; )

