Founded to the east of the river, it was protected from the yearly Nile flood and surrounded by a high wall to guard against invaders.
It is always left unprotected and there is nothing to help it. 
mnli hypothesis: It is always left unprotected and there is nothing to help it.  premise: Founded to the east of the river, it was protected from the yearly Nile flood and surrounded by a high wall to guard against invaders.