Dictionary.com gave me a great place to start (after a few bad starts)...
OHG, perfect, way before the time I'm researching. Flasche, German for flask, is the term that finally opened the search engines to what I wanted, though perhaps not exactly how I thought I wanted them. Flasche turns into the modern English equivalent of a bottle.Origin:
1375–1425; late Middle English: cask, keg < Anglo-French, Old French flaske < Late Latin flasca, earlier flascō, of uncertain origin; compare Old English flasce, flaxe, Old High German flasca ( German flasche ); compare flagon
|Children of the Planets: Luna (Moon) by Meister Hausbuch (c1475-85)|
Not the easiest to see, that's why I've provided a detail, but that looks like a drinking flask hanging from the man's spear on the upper right side of the drawing.
There is also a square flasche in Hans Baldung Grien's Apostelscheidung (1521) and I know I've seen another, but I've lost it for the moment.
A side trip gave me another word to throw into all of this which is even older than flasche... flehtanan (“to plait, braid”), from the practice of plaiting or wrapping bottles in straw casing.
[EDIT: Thanks to a comment which included a larger resolution image, I have updated these images for better viewing.]