gray friars

from The Collaborative International Dictionary of English v.0.48

Franciscan \Fran*cis"can\, n. (R.C.Ch.)
   A monk or friar of the Order of St. Francis, a large and
   zealous order of mendicant monks founded in 1209 by St.
   Francis of Assisi. They are called also {Friars Minor}; and
   in England, {Gray Friars}, because they wear a gray habit.
   [1913 Webster]