Using the same rationale for his calculations for Augustinian numbers in 1517 as he did for those of the year 1357, the twentieth-century Augustinian historian David Gutierrez O.S.A proposed a tally of 8,000 members of the Order of Saint Augustine in 1517, i.e., on the eve of the Protestant Reformation beginning in Germany.
In 1971, Augustinian historian David Gutierrez O.S.A. discounted and hopefully laid to rest the popular reference to there being in the year 1500 about 2,000 Augustinian houses with 30,000 members, plus an additional 300 monasteries of nuns. He traced this erroneous calculation back to an Augustinian writer, James Battista degli Aloysi O.S.A., alias Alovisiani, who died in 1505. Coccius Sabellicus repeated Aloysi's figures in his book published in Basel in 1560, and these exaggerated figures then kept reappearing in publications as recently as fifty years ago. [See the wise historiographical corrections of F. Roth O.S.A., The English Austin Friars 1249-1538 (New York: 1966), p.217]
Gutierrez stated that, in the absence of any substantive figures, Aloysi had made an estimate of Augustinian numbers on the false premise of equating them with the large membership of the Franciscan and Dominican Orders at that time. Gutierrez held that there was no historical justification for presuming that the Augustinian tally should approximate that of these two larger mendicant orders. He noted, furthermore, that scholars late in the twentieth century generally suspected that these numerical estimates of the religious orders founded by Dominic and Francis were themselves also exaggerated.
No listing of the houses of the Order based on factual information existed prior to documents compiled by Prior General Girolamo Seripando O.S.A. between 1539 and 1551, and Ippolito Fabriani O.S.A. in 1602-1607. Reducing Seripando's list on the basis of subsequent confirmed sources, a fair calculation suggests the existence of 800 Augustinian houses in 1545. Seripando's list, however, did not refer to the number of Augustinians in any of these houses, although an estimation of ten Augustinians per house (i.e., giving a total of 8,000 Augustinians) still appears to produce a generous tally rather than a cautious one.