Houses are buildings that support population. They support 10 population. They cost 50 wood to build, and you can have a maximum of 10 houses.
Differences to AoE and AoKEdit
In AoE and AoK, all units only take one population. Also, you can build unlimited houses. However, in AoE and AoK, the population maximum is usually much lower than in AoM. It is commonly 75 in AoE and 200 in AoK. AoM has a maximum population of 300. It is not usually hard to get maximum population in AoE and AoK because you can build unlimited houses, while in AoM, you have to find enough settlements to build town centers on.