>From recorded data, we can see that everyone seemed to play e4 in the 1500s. Over centuries, moves like d4, Nf3 or c4 emerged as credible and fashionable alter

>From recorded data, we can see that everyone seemed to play e4 in the 1500s. Over centuries, moves like d4, Nf3 or c4 emerged as credible and fashionable alternatives. The graph they have seems to suggest the opposite - nobody playing e4, just d4 early on (and AZ also gravitating most towards d4).