Too much emphasis on the narrative of the “return” of the “historically marginalised Shia communities”, however, risks overshadowing the living experience of a region in which religious boundaries were, for most of its history, shifting, blurred, and ambiguous.
Despite what the ongoing debates would seem to imply, Sunnis and Shias, but also Christians, Jews and other religious groups or confessions have in fact lived for centuries in the region, reaching a level of coexistence - a concept that does not erase the existence of boundaries but implicitly acknowledges that such boundaries are negotiable - higher than any registered in most of the rest of the world, Europe included.
This should not suggest that communal conflict was historically unknown. As this article also confirms, instances of Sunni-Shia violence have been documented as early as the Middle Ages. Yet, they don’t mirror the actual history of most of the region’s past (pdf). More importantly, their nature and scope are hardly comparable to more recent times.