Mogtasilah
From BiblePortal Wikipedia
Mogtasilah [1]
(i.e., those who wash themselves) is a name which mediaeval Arabic writers gave to a sect of Christians' said to have flourished on the eastern shore of the Dead Sea. Recent investigations render it probable that they were the Zabians (from צבע = טבע , Βαπτίζειν , to wash), or Mendceans (q.v.) of the present day.