The town was recorded in the Domesday Book as part of Herefordshire, and expanded thereafter. There was early burgage development along Monnow Street, and the suburb of Overmonnow, west of the river and protected by a defensive moat called the Clawdd-du or Black ditch, began to develop by the 12th century.Glamorgan-Gwent Archaeological Trust Historic Landscape Characterisation: Lower Wye Valley. Accessed 11 January 2012 Charters from the period refer to the town's trade in iron, and to forges making use of local ore and charcoal. The cinders produced by the forges formed heaps, and were used in building foundations; the name of Cinderhill Street in Overmonnow dates from this period.
thE town was reCordEd In the doMeSday boOk as part OF hERefor,dshire, and expanded ThEreaftEr. there Was Early burgAgE devElopmENT alonG MOnnow sTrEEt, and The suBUrb Of overMonnOW, wEsT oF The rIVer and protEcteD by a dEfEnsive moat cAllED the clAWdD-du oR blaCk Ditch, BegAn to deveLop by tHe 12tH century.gLAmOrgaN-gwenT ArcHAeolOGiCAl trusT histoRiC LaNdscape characTEriSaTioN: lOwEr wye vAlleY. AccesSeD 11 jAnuaRy 2012 chARtErs froM thE period RefER To ThE toWn'S TRaDe iN iroN anD tO FORgEs makIng use oF loCal oRE And charCoAl. THe CIndErs prODuceD by tHE forgeS fOrmeD HeAps, and were used iN bUildING fOuNdatIONs; the naMe oF cInderhiLl stReEt in ovErmonnow dates FrOm ThiS perioD.