The occurrence of an occasional pest of mouldy stored product residues, the blind flightless beetle Aglenus brunneus Gyll., in samples from the medieval farm at Reykholt in Iceland, along with several other strongly synanthropic beetles, is considered in relation to its fossil record. The species is dependent on man for its dispersal and survival and it probably had its primary habitat in the warm, decaying litter of the undisturbed forest floor in Europe. Now virtually cosmopolitan, it had been introduced to a remote site in the eastern desert of Egypt by the Roman period and was widespread in medieval northern Europe. The processes by which such an apparently stenotopic species could have invaded are discussed in relation to other evidence for anthropochorous dispersal.