Complex sentence: Valentinian literature described the Primal Being or "Bythos" as the beginning of all things who, after ages of silence and contemplation, gave rise to other beings by a process of emanation.
Split into simpler sentences: Valentinian literature described the primal being, called "Bythos", as the beginning of all things. After ages of silence and contemplation, Bythos gave rise to other beings by a process of emanation.