I'm currently reading some books about romanesque architecture. I would like to know the roles of towers that many religious buildings have. I have some guesses, so I would like you to tell me if these guesses are true or wrong.
First example : St. Pierre Cathedrale (Treves)
we can see small rounded towers. My guess, everytime, that kind of tower is used for stairs, eventually to defend the building at some point.
The squared tower, my guess, are present as a symbol of the gate of the celestial Jerusalem, but for what else are they used ? My personal experience push me to say : for bells, but bells don't occupy the whole tower.
Also, I'm curious if the ground section of a tower is linked to its height.
another example : St. Michel (Hildesheim)
as we can see, there is only crossing towers and small rounded towers. I guess, the squared towers are used for bells too.
the part in italic contains mistake, see the comments
Too finish, it seems (maybe I'm wrong on that point) that temples used before christianity romans/greeks (pagan) had twin towers (like the one we can see on the picture of St. Pierre). So I would like to know if the celestial representation of jerusalem has it origin in roman/greek temple (pagan).