and youd blame religion as the sole reason?
you may want to change your graph a bit
around the dark ages, arab and chinese traders kept most of the knowledge lost in the dark ages. this knowledge was not lost, in fact most of it was reintroduced right before the western renaissance. the western world was plunged into scientific dis-array, but the rest of the world flourished. knowledge was traded and built upon.
to blame religion as the sole cause of technological stagnation is a silly notion. the world is, was and always will be round. to base the development of the earth on the concepts of the western world is frankly supremacist in nature.