Ditch-Filling Roman "Tortoise" Siege Machine

This instrument was designed and built to fill in ditches around a fortress or 

fortified city.  The men entered from the rear (to the right) with their baskets or 

sacks of ditch fill (sod, fachines, rock, or dirt).   The machines top and sides 

would first be planked solidly and then covered with wet and raw hides against 

any attempts to use fire against the machine.

According to Athenaeus, the ditch-filling tortoise could be rolled sideways, as 

well as backwards and forwards, probably by briefly raising each corner in turn,

and changing the orientation of the axle (see page 16 illus.).  Without 

experimentation, it is unclear how this was accomplished, but the large frame

would have allowed a dozen or more men to congregate around each wheel 

assembly  and jointly take its weight.  With the machine in position, there 

would have been ample space in the interior for men to work unhindered, 

evening out depressions in the ground.  The gap between the rafters and the 

ground would have been sufficient to allow baskets of earth and rubble to be 

brought in at the rear, from which they could be dragged forward for the task 

of ditch-filling.

The scene (Plate A) is based on the siege  of Halicarnassus in 334 BC, when 

Alexander  was obliged to fill the newly cut 13. 5m wide, 7m deep defensive 

ditch, in order to bring up heavy machinery.  The remains of the fortifications 

suggest that the curtain was a single-line, single-story affair, but not enough 

survives for an accurate picture.  Here, the reconstruction is based on the defences

of Paestum (Italy), generally thought to have been built around 330 BC.   

The approximately 9m high wall is crowned by a closed battlement with 

shuttered windows, as a defense against escalade.

Reference:  Duncan B. Campbell, Brian Delf (illus.), "Greek and Roman Siege 

Machinery, 399 BC -- AD 363," New Vanguard-78, (Osprey Pub., 2003), 

Page 44.  (ISBN 1-84176-605-4)