Attempts to reconstruct these ancient weapons began at the end of the 19th century, based on rough translations of ancient authors. It was only during the 20th century, however, that many of the reconstructions began to make any sense as a weapon. By bringing in modern engineers, progress was made with the ancient systems of measurement. By redesigning the reconstructions using the new information, archaeologists in that specialty were able to recognize certain finds from Roman military sites, and identify them as ballistae. The information gained from the excavations was fed into the next generation of reconstructions and so on.