This paper presents a new edition of a boundary stone between Capua (on Crete) and Knossos. I identify the post of Publius Messius Campanus as procurator Campaniae rather than procurator Caesaris. The appearance of the procurator Campaniae on Crete is linked to a dispute between the colony of Capua and a private citizen called Plotius Plebeius. This new reading has several important historical consequences: first, it is the earliest attestation of a procurator Campaniae (and the first outside Italy); second, it offers a new interpretation of the juridical category of Knossian lands as part of the ager vectigalis of the Italian colony of Capua in the form of a praefectura Campana or Capuensis; third, it proposes a reinterpretation of the process of arbitration between a public entity (Capua) and a private owner.