Read this: Human sacrifice in ancient Rome was rare but documented. After the Roman defeat at Cannae two Gauls and two Greeks were buried under the Forum Boarium, in a stone chamber "which had on a previous occasion [228 BC] also been polluted by human victims, a practice most repulsive to Roman feelings". Livy avoids the word "sacrifice" in connection with this bloodless human life-offering; Plutarch does not. The rite was apparently repeated in 113 BC, preparatory to an invasion of Gaul. Its religious dimensions and purpose remain uncertain.

When was the invasion of Gaul by Rome?
What is the answer? (If it cannot be answered, return "unanswerable")
113 BC