Certainly not a container for holy water! My guess a
Roman "chamber"
pot for collecting urine (the ancient source of ammonia) to be used in the processing of hides, bleaching of cotton etc! Depending on size (no
scale present on the photo) it may have been positioned in a public place for urine
collection purposes, if of the larger variety. If smaller, it may have served the same purpose in a domestic context. To my eye and based on the two
handle design (that is a lot of piss to haul about) it looks like the former...a public
collection piss
pot!...the
function of which was to collect urine as a feedstock for industrial processing purposes.
Plinius has described how there were large receptacles in the streets of cities such as Rome and Pompeii into which chamber pots of urine were emptied. The urine was then collected by fullers. The fermentation of the urine produced ammonia, and this was then used to bleach linen. This continued to be done right up to the late Middle Ages in Europe.From an article in the World Journal of Urology (downlaod available here :http://www.springerlink.com/content/k2twwb7c1x3g8b83/)
Some historical aspects of urinals and urine receptaclesJ. J. Mattelaer World J Urology (1999) 17: 145±150