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Medieval English Woman's Costume: A Woman of the Time of Henry II. (1154-1189)
"There is a chin-band to be seen passing under the whimple; this band is pinned to hold it round the head."
See the accompanying article: Women's Clothing in the Time of Henry the Second and Eleanor of Aquitaine. Source: Calthrop, Dion Clayton. English Costume: I. Early English. London, 1906.