  Roman Empire is renowned for sharp logical design and outstanding building
quality of its road system. Many roads built by Romans are still use in
continental Europe and UK. The Roman roads were built for military
transportations with efficiency in mind, as straight as possible. Thus the
roads make an ideal test-bed for developing experimental laboratory techniques
for evaluating man-made transport systems using living creatures. We imitate
development of road networks in Iron Age Italy using slime mould Physarum
polycephalum. We represent ten Roman cities with oat flakes, inoculate the
slime mould in Roma, wait till slime mould spans all flakes-cities with its
network of protoplasmic tubes, and analyse structures of the protoplasmic
networks. We found that most Roman roads, apart of those linking Placentia to
Bononia and Genua to Florenzia are represented in development of Physarum
polycephalum. Transport networks developed by Romans and by slime mould show
strong affinity of planar proximity graphs, and particular minimum spanning
tree. Based on laboratory experiments we reconstructed a speculative sequence
of road development in Iron Age Italy.
