ABSTRACT
The turbulence of the Migration Period and the great epidemics of plague in the sixth century left behind a western world that was more empty and desolate than it had been in the later years of the Roman Empire. In the absence of state institutions supported by tax flows, non-aristocratic, free, able-bodied men had two public obligations which in the Roman Empire had been delegated to professionals: military service and the attendance of public courts of justice. The armies of the Frankish and Visigothic kingdoms around 600 seem to have been built up of free landowners who were all considered to be 'Franks' and 'Goths' respectively, whatever their ethnic background, around a core of royal and aristocratic retinues. The core of Pirenne's theory is that the Migration Period left the economic system of Late Antiquity, centred on the Mediterranean and linking southern Europe to the Middle East, largely unaffected.
