The evidence for this Latin grammarian is extremely sparse.  The single manuscript that transmits his Ars - in a passage that Kaster suspects of being an interpolation - mentions a certain Cledonius Romanus senator Constantinopolitanus grammaticus: although the absence of punctuation complicates our identification of his origins, the most recent scholars maintain that he was active at Constantinople after the first quarter of the 5^th c. (Gatti).  A terminus post quem can be established by the fact that Cledonius seems to have relied on Servius’ commentary on Donatus; a terminus ante quem is established by the very codex that transmits the Ars, which Keil argues is of the 6^th c., Sinner of the 7^th c.  [S. Mollea; tr. C. L. Caterine]