Apr250100999 - 0 A.D.no infoCirca 50 A.D. Athenaeus of Attilia, writing on Purification of Water, cites a single, double, and triple filtration process as producing water of the greatest purity. Category: 999 - 0 A.D., no info25. 4. 0100Post navigationPreviousPrevious post:18 A.D. – Roman Baths (thermae) opened by Vipsanius AgrippaNextNext post:Circa 77 A.D. – Use of lime and aluminous earth