Watch List notes:

Augustus (27 BC - 14 AD) with Agrippa. AR Denarius, 13 BC. C. Sulpicius Platorinus moneyer. Obv. CAESAR AVGVSTVS. Bare head of Augustus right. Rev. M AGRIPPA PLATORI [NVS III VIR]. Bare head of M. Agrippa right. RIC 408. C. 3 (Fr. 150). AR. g. 3.78 mm. 18.50 RR. Very rare and in excellent condition for the issue. Two superb portraits and enchanting light iridescent tone. Insignificant banker's mark on obverse, otherwise EF/About EF. Marcus Agrippa was the architect of Augustus' military success for more than three decades [...].
On this coin he is honored with an imperial portrait, which not only marked him as the heir-apparent to Augustus, but which identified his position within the dynasty. The occasion was the joint-renewal of tribunician powers of Augustus and Agrippa in 13 B.C. The ceremony and its related celebrations were held in Rome, to which both men had recently returned – Augustus from Gaul and Agrippa from the East. It was a moment of peak glory for Agrippa, though it would not long endure, for he died the following year. (NAC 101, 83 note).