Hello,
yesterday I found myself on an unsolvable map: I was the only player on an island - it was not a tiny one so it took me a while to clear it and find out. But because there is no raise land spell (at least for my custom sov) and you can't have ships or flying units I could not make contact with any other factions. Victory by Spell of Making was also not possible because my island did not have a fire shard available...
Regards,
Markus