Newsweek article A hoard of 5,600 silver coins from the Roman Empire dating back nearly 2,000 years has been found in Germany. I want to share this webpage with you. https://www.newsweek.com/cache-thousands-ancient-roman-silver-coins-found-river-1653112 A type of Roman wishing well?
I lived near that area for 6 years. They frowned HEAVILY on metal detecting due to so many explosives from two wars still buried (granades, mines, unexploded bombs, ect.) I see their point.
Makes sense the oldest was Nero. He reformed silver coinage down to purity levels used for the 2nd century, so anything older was known to contain more silver than later examples. See this often in 2nd century hoards, the oldest coin being reformed Nero pieces.