What is "pecsaetan"

The Pecsætan (, literally " Peak-dweller"), also called Peaklanders or Peakrills in modern English, were an Anglo Saxon tribe who inhabited the central and northern parts of the Peak District area in England. The area was historically the home of the southern clan of the Brigantes, a Brythonic tribe, before the Anglo-Saxon invasion. The very early Derbyshire settlements, in what is now known as the Peak District, were those of the West Angles. This tribe advanced up the valleys of the rivers Derwent and Dove during their northern conquests in the 6th century. They became known locally as the Pecsætan. Later their territory formed the northern division of Mercia, and in 848 the Mercian Witenagemot assembled at Repton.