"More than likely it's a Norman font, dating back to perhaps around the ninth century, we're not sure," Cathedral administrator, Fr Brian Nichols, told ABC News.
"Bishop Wilson, the first Catholic bishop of Hobart Town brought it with him, he may have brought it with him on the ship."
Electrician Martin Jackson also noted that rewiring of the cathedral involves getting up into the arches to clean out decades of dust.
"Which really shows all the main sort of historical events of Hobart - the coal dust, the two major bushfires, the 1967 bushfires," he said.
"It's quite interesting to sift through that sort of stuff."
The organ pipes are being pulled out and the stonework repaired."Obviously someone has been looking after this church, that ... no fire or anything has actually destroyed it," said Edward Gauden, one of the people behind the restoration.
The restoration work has closed the cathedral for the first time in more than 125 years but the archdiocese hopes the project will keep St Mary's open for at least another century.
"The longer you leave it we leave it for other generations," Fr Nichols said.
Ashes to ashes, dust to dust, restoration of ageing cathedral a must (ABC News, 29/5/08)