Robert distinguished himself with an extraordinarily long reign for the time.
His 35-year reign was marked by his attempts to expand the royal domain by any means, especially by his long struggle to gain the Duchy of Burgundy.
His policies earned him many enemies, including three of his sons.
He was also known for his difficult marriages: he married three times, annulling two of these and attempting to annul the third, prevented only by the Pope's refusal to accept a third annulment.