Augustus fell dangerously ill in 23 BC and did not expect to recover. The model of late imperial succession suggested that the closest male relative would succeed, despite the fact that Marcellus had held no office and lacked military experience. His marriage to Augustus' daughter seemed to be a strong indicator, but Augustus seems to have planned his succession so that the strongest and most experienced member of his family would succeed. He gave his signet ring to his lifelong friend and general Marcus Vipsanius Agrippa, a sign that Agrippa would succeed him if he were to die. This probably angered Marcellus, who expected to be his heir, though Augustus may have meant for Agrippa to run the empire until Marcellus became more experienced leading armies.