A common treasure map is an item in Evony TKR (The King's Return). It can be found after killing certain monsters or bosses, with some of them listed below.
The description of Common Treasure Map in Evony TKR says:
Use it to locate a Lv1 Relic to search for Treasures.
Common Treasure Map is known to drop from a number of bosses or monsters upon killing, including Zombie, Redcap and Centaur.
Note: This list may be incomplete.