16838
The idea that the arcuballista was a crossbow is based on the fact that Vegetius refers to it and the " manuballista " , which was torsion powered , separately .
 Vegetius
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 Vegetius