Prerequisites: Stable level 20, Rally Point level 10, Tribe: Romans, version 3.5 or higher. It is also often referred to as "Horse Drinking Trough", or HDT for short. The horse drinking trough of the Romans decreases the training time of cavalry and the upkeep of these troops as well. - Accelerates the production time of cavalry units by 1% per level. - At different levels the HDT lowers the crop consumption of all Roman cavalry units that are stationed within that village. - The maximum level the Horse Drinking Trough can be upgraded to is 20. Building Costs, Upkeep, and Culture Points