The Sage Tower acts as the event center of your cities. Uniting your cities, only one center can be constructed, serving all your four or five cities. Items won in special events can be exchanged in the Sage Tower, while other items such as gear and Gems can be exchanged for materials acquired in campaign primarily. As there are a large number of Sage Tower trades, this articles is meant to give an overview of these for less-experienced players.
One of the basics aspects of the game Kingdoms of Middle Earth is acquiring and building up your cities. When starting the game, you have one city, but this can be expanded to 4 cities, and a special 5th Lake-Town city. Cities can contain a number of different buildings, each with their own function and dependencies.
In this article, I will summarize what each building does. Two types of buildings are mentioned: The City buildings contained within your City Walls, and the Field, or resource buildings, which are constructed on field plots. Buildings from the 5th Lake-Town city will come in a separate article.
NOTE: Images of the buildings are courtesy of the HobbitArmies Wikia page here
At the time of writing that piece, the feature had not been fully implemented yet, but it has in the mean time, and it is such an addition it merits its own article. So here, I will lay out all the necessary information you need about this feature.