From Wiki Grepolis
The Senate is the administrative centre of your polis. Here, you can order workers to build, expand or demolish buildings. It is one of the most key buildings in Grepolis and without it, your polis will be unable to grow or expand.
In the Senate, you can build new buildings, expand buildings or demolish buildings (which requires Senate level 15). The higher the level of your Senate, the quicker buildings are constructed or expanded.
The Senate is a key requirement for most buildings throughout Grepolis. You will need a certain level Senate to build buildings such as the Barracks, Academy as well as all the special buildings and most of the other buildings that you may build in your city.
The Senate is available from the beginning of the game. There are no requirements that need to be fulfilled to build the Senate, though most other building requirements throughout the game involve the Senate.
The maximum level of the Senate is 25. The Senate's appearance changes depending on the level of the Senate.
|Level 1 - 7||Level 8 - 15||Level 16 +|
Although the Senate is the key factor in construction speed, some researches affect how quick a building is constructed or expanded. For example, having the technology Crane researched will speed up construction by 10%. The table below is for speed 1. If you are playing on a higher world speed, for example, speed 2, divide the build time by the world speed.
Cost rises exponentially, like all other buildings. The table below shows this.
Maximum Level : 25