The idea that scientific advancement stopped for 1000 years during the middle ages is wrong and dumb. The shining example here is the Gutenburg printing press but there are plenty of other things thar were invented and discovered during the middle ages.
The idea that this vacuum in discovery was caused by religion is based on an extremely naive and incomplete understanding of history.
I'd also like to point out that discovery thrived in the middle east during the middle ages, and the middle east was also a very religious part of the world.
Does it matter who destroyed the Romans, it was christianity that kept further invention and past advancements in the dark, also maybe China isn't included as the graph displays advancement in relation to christianity and it's spread.
Not only is the graph wrong, it's also dumb, which is really quite a bad combination of things to be if you happen to be a graph.