The Stone Keep is a building.
This building is an improvement of the Motte-and-Bailey Castle. It therefore requires the latter to be built.
The creation of the Gunpowder Factory is only possible if the technology Stone Keep has been enabled in the province.
This building requires 18000 man-days
The construction of the building requires 4 political points, 5,000 gold, 50 wood and 120 stones.
The Stone Keep can employ up to 200 researchers (Motte-and-Bailey Castle can employ 100)
This building is a prerequisite to research the technologies: