Kammala jumla mai zuwa: A lokacin mulkin Sarki Offa (757-796) Tamworth ita ce babban birnin Mercia. Offa ya zama mafi girman iko a cikin abin da ke yanzu Ingila, kuma wannan ya nuna a Tamworth; Offa ya gina abin da aka bayyana a matsayin fadar sarauta a Tamworth, duk da haka wannan kusan tabbas itace ne da ginin katako (kamar yadda aka yi
mafi yawan gine-gine a Anglo-Saxon Ingila) wanda ya bar ɗan alama ta zahiri, don haka ba a taɓa gano wurin fadar Offa ba, kodayake tonowa a arewacin titin Bolebridge a cikin 1968 ya bayyana abin da ya zama kamar siffar babban ginin Saxon. Ofaya daga cikin rubuce-rubucen rubuce-rubucen farko da suka tsira da suka ambaci Tamworth ya fito ne daga zamanin Offa; kyautar ƙasa ga limamai a Worcester wanda ya fito daga 781, wanda Offa, Sarkin Mercia ya sanya hannu, wanda aka yi jawabi daga fadarsa ta sarauta a "Tamworthie". Tamworth ya kasance birni mafi girma a cikin Midlands na Ingila lokacin da birni mafi girma na Birmingham na yau yana cikin ƙuruciya. Wannan yafi yawa ne saboda matsayinta na dabara a wurin haduwar kogin Tame da Anker, yana sanya garin daidai a matsayin cibiyar kasuwanci da masana'antu.