When did roman ideas about law and government spread over a large area

If we are talking about when the Roman Empire started, I believe it is because they believed they were right about their belief. So perhaps they wanted to spread their beliefs because they believed it was right. During 300 b.c.e, they were expanding their land into Italy and conquering new lands and gaining new citizens along the way. They also acquired many allies along the way.

The holo caust ya feel me