 The same sentence in Vulgar Latin could have been *"(h)omo stat in foro", "the man stands in/at the marketplace", replacing the "est" (from "esse") with "stat" (from "stare"), because "standing" was what was perceived as what the man was actually doing.The use of "stare" in this case was still semantically transparent assuming that it meant "to stand", but soon the shift from "esse" to "stare" became more widespread.In the Iberian peninsula "esse" ended up only denoting natural qualities that would not change, while "stare" was applied to transient qualities and location.