GIOVANNI, DIACONO. - Neapolitan chronicler, who lived in the second half of the 9th century and the beginning of the 10th. He was rector of the diakonia of S. Gennaro, and the author not of the entire Liber pontificalis Ecclesiae neapolitanae, as was once believed, but only of its second part, which embraces the biographies of the bishops of Naples from Paul II, elected in 762, to Athanasius I, who died on July 15, 872; the work was written in his youth, with accuracy and impartiality (v. RIS, I, II, pp. 291-318).
He also composed: Acta s. Ianuarii (cf. Acta SS. Septembris, VI, Paris 1867, pp. 874-78); Acta translationis s. Sosii diaconi (ibid., pp. 879-84); Acta translationis s. Severini (ibid. Ianuarii, I, Paris 1863, pp. 497-99); Vita s. Nicolai episc. Myrensis (cf. N. C. Falconio, S. Nicolai... acta primigenia, Naples 1851, p. 112 ff.); Martyrium s. Procopii episc. Tauromenii (cf. RIS, I, II, pp. 269-73); the translation from Greek into Latin of the martyrdom of the Forty Martyrs of Sebaste: Vita martyrum XL Sebastenorum (Acta SS. Martii, II, Paris 1865, pp. 22-25).