@Paul, that all depends on which dictionary you use to define "disbelief". Disbelief can mean an active "I don't believe that!" or a more passive "I have no belief" (i.e. a synonym for non-belief).
Regardless, since atheists come in all forms, from non-believers to positive disbelievers, the non-believing atheists (who "lack" belief) must have come first.
Regardless, since atheists come in all forms, from non-believers to positive disbelievers, the non-believing atheists (who "lack" belief) must have come first.