Chapman were itinerant merchants , pedlars or packmen . Burn's in Tam O'Shanter wrote in his opening line " When Chapmen billies leave the street " .Prior to the Statute Labour Acts , roads were virtually tracks and the packmen or chapmen would go round the clachans and villages selling their wares . They would often have a chain of some 5 to 10 ponies in a line with panniers strapped to their backs At night they would be tethered in a circle to prevent escape . Perthshire has numerous pack bridges still in good condition and built in nthe 17th century . There is a fine example in Alyth and a number around Crieff ( particularly Barvick and Monzie ) . Narrow and just wide enough to allow the ponies to cross in line . The examination of the old trades in our research is an integral part of our studies . Social history and family history are bed mates . Col in Crieff