Construction beginning/end
At the place where the holy city once stood the brothers gather followers and start building an immense Tower to symbolize the unity, when the first stone begins to be laid, the age of construction begins.
The Seven Brothers after several long discussions between themselves decided to start to build a place where everyone could come feel safe either for personal or economic reasons. The place they chose was where the glorious city once stood, so together with volunteers from each ethnic group within the Union, they set about building a tower and a city around it. Which is seen to have been such a grand and important event that it started a whole new age later recognized as the age of construction, officially beginning when they lay the first stone of the towers foundation.