Question: Where is the likely source of the change to the manipular formation?
Sentence: This change is sometimes attributed to Marcus Furius Camillus and placed shortly after the Gallic invasion of 390 BC; it is more likely, however, that they were copied from Rome's Samnite enemies to the south, possibly as a result of Samnite victories during the Second Samnite War (326 to 304 BC).
Answer in sentence: yes