VIENNA (Reuters) - An 800-year-old map, the sole surviving copy of a chart used by the Roman Empire's courier service, was put on show for just one day on Monday after being accorded "Memory of the World" status by UNESCO.
The parchment scroll, nearly 7 metres (yards) long, could only be displayed briefly because too much light would damage it, before it was returned to storage at Austria's National Library, where it has been since 1738.
Named Tabula Peutingeriana after the German antiquarian who owned it in the 16th century, the map shows roads linking some 4,000 settlements as well as mountains, rivers and forests from Spain in the west to China in the east.
From north to south, the map covers the British Isles to north Africa. But because the scroll is just over 30 cms (12 inches) high, the north-south axis is greatly compressed, depicting the Mediterranean Sea as a small stretch of blue squeezed between today's Croatia and Italy.
"It's a bit like when you look at a map of the Vienna underground system -- it's not accurate but it gives you a good idea of how to get around," Andreas Fingernagel of the National Library told journalists at the showing.
The document, preserved in 11 segments, was written on parchment at the end of the 12th century as a medieval facsimile imitating the book scroll used in Roman antiquity.
The original would have been used by Roman administrators and couriers, telling them the choice of roads, how long it would take to go somewhere and, through a series of icons, how comfortable their next rest stop would be.
The copy was probably made in southern Germany at the end of the 12th century, said Fingernagel.
The missing original -- none are known to have survived -- probably dated from the first half of the 5th century, and so far only half of the 4,000 settlements have been identified, said Fingernagel.
Globally, 158 documents have UNESCO Memory of the World status, which aims to preserve and disseminate valuable archive treasures and library collections. UNESCO also grants World Heritage status to historic architecture.
(editing by Tim Pearce)