en.wikipedia.org/wiki/Roman_legion

For the imperial period described in this section, the wording "elected" is wrong. Cassius Dio explicitly says that the emperor himself selects knights to be sent out as military tribunes. In other words, tribunes in the imperial system were appointed/selected from above, not elected by the soldiers or by popular vote. The article’s phrase likely confuses the imperial office with earlier Republican practice.

This sentence assigns the start of the 4th-century restructuring to Constantine II, but standard references place the relevant reforms under Constantine I (and in continuity with Diocletian’s reforms). Britannica notes that Between 325 and 337 Constantine effected important reforms, continuing Diocletian’s work, while Britannica’s biography of Constantine II identifies him as emperor only from 337 to 340. A classic Journal of Roman Studies article likewise summarizes the distinction as Diocletian is the augmenter, Constantine the reformer, with Constantine creating the field army of palatini and comitatenses. So the process did not begin under Constantine II.

The imperial Roman navy was not primarily manned by freed slaves. Scholarly work on naval recruitment states that the Roman fleets of the imperial period were crewed by provincials, and another academic summary says recruits for the imperial navy were almost invariably peregrine by origin, non-Roman but freeborn men. That directly conflicts with the article’s wording that the permanent navy was where the liberti (freed slaves) served. Some imperial freedmen did hold administrative posts in the fleets, but that is different from saying the navy itself was staffed by freed slaves.