Although intimations of the concept of inertia are suggested sporadically in ancient discussion of motion, the salient point is that Newton's theory differed from ancient understandings in key ways, such as an external force being a requirement for violent motion in Aristotle's theory.
Intimations of the concept of inertia are suggested sporadically in ancient discussion of motion. Newton's theory differed from ancient understandings in key ways. This was such as an external force. This external force was being a requirement for violent motion in Aristotle's theory. The salient point is this.