Well, i looked through my comp n found this old SS of when i played RYLII, this is what a Guild Fort looked like. This was my guilds Tower XD
When you were in hostility with a guild n u walked into the territory owned by that guild, they could ATTK you with no problems.
TERRITORY SYSTEM
The player is able to specify the territory that will become his own to develop that territory to increase its wealth and benefits. The player can form a party or community to wage war against another community who are friends or foes. A player can become the "feudal lord" or chief of that particular area/territory by being voted by other players. The feudal lord must have his/her own strategic unit in the game and is responsible for waging wars against others.
DEVELOPMENT, CONSTRUCTIONS, INVESTMENT CONCEPT
No matter what policy or regulations are set by the feudal word, a character is still able to manage his own territory such as constructing buildings, receiving contributions and investing in the territory. In other words, to become a strong clan or group, each member needs to contribute to the community and support its war strategy policy.
O god the good old dayz

We used to have so many guild wars, we had one of the biggest forts, for a short time