there are 8600 cities containing the substring "(historical)" in their names. Nearly all of them are in the US.
What are these "historical" cities? They seem like old towns that don't exist anymore. Is this correct? If it is, shouldn't they be deleted from Geonames?
There are categories for places like:
[list]BTL battlefield a site of a land battle of historical importance
HSTS historical site a place of historical importance
RUIN ruin(s) a destroyed or decayed structure which is no longer functional
PPLQ abandoned populated place
[/list]
Some of these could classed as those or put as alternate names of their successor places. (Personally, I like to add the old historic names of places)
I prefer solutions that do not destroy information.