Re-examination of the well-known Atarbos base in the Akropolis Museum shows that the monument had two distinct phases which have generally been ignored in previous discussions: it originally consisted of a pillar supported by the extant right block decorated with the relief of purrhikhistai; subsequently, the pillar was removed, the base was doubled in size, and three bronze statues were erected. Close examination of the remains and the style of the reliefs indicates that the original period dates to 323/2 BC (...) with the second phase following within a year. In light of this chronology, the prosopography of the family is reviewed and new restorations are suggested for the base's inscriptions. In its first phase, the monument belonged to a newly identified series of memorials consisting of rectangular bases with pillars supporting either a relief or a Panathenaic amphora. Such structures commemorated victories in various tribal events of the Panathenaia and were set up both by individuals and by tribes. The earliest known example appears in a vase painting of c. 430-420 and the type continued to be used until at least 323/2. The identification of this series also provides further evidence for history of the purrhikhe, the cyc1ic chorus, the anthippasia, and the apobatic race at the Panathenaia, as well as the identities of specific victors in these contests. (shrink)