There is a problem in counting the Pope Stephens.
Stephen II was elected on the death of his predecessor Pope Zacharias on or about March 23, 752. Three days later he died of apoplexy before he had been consecrated. Therefore some list-makers do not count him as having been pope, throwing off the Stephen-count. Modern historians typically include him, but one does sometimes see later Stephens numbered with parentheses, so that his immediate successor could be denoted Stephen (II) III.
|List of popes||
Pope Stephen III