I got up to 650, which matches historical evidence.
Ober-Olm, a village about 10k from Mainz, dates back to the early Stone Age and finds in recent (i.e 1866…) years confirm a significant Roman presence.
Not from the mighty elm trees that characterised the village for centuries, that’s for sure.
The Latin “ulmus” didn’t migrate to the German language (as “Ulme”) until the 12th C and the name existed long before that.The general consensus is that the Seltz, a stream which winds its way through the valley followed a Roman convention and was named Ulmena.
The last elm tree was put out of its misery in 1995, a victim of the Dutch elm disease which has terrorised the European landscape in recent decades, and a massive chunk of it stands as a sentinel at the lower end of the village.