en.wikipedia.org/wiki/Gallienus

The infobox labels Saloninus as a co-emperor in July 260, but the evidence I checked dates his assumption of the Augustus title later.

• The University of Osnabrück chronology for Gallienus and Salonina states: "Herbst 260 Saloninus nimmt den Augustustitel in Köln an" (“Autumn 260 Saloninus takes the title of Augustus in Cologne”).
• The Berlin Münzkabinett authority file likewise says: "In autumn of AD 260 Saloninus took the title of Augustus in Cologne."

Since "co-emperor" here means Augustus rather than Caesar, dating Saloninus to July 260 is incorrect; July 260 is associated with the opening phase of Postumus's revolt, not Saloninus's documented elevation to Augustus.

This caption appears to be a transcription error.

The actual Wikimedia Commons file used for this image identifies the coin as:

• "LEG V MAC VI P VI F"
• "Coin issued to celebrate Legio V Macedonica"

An independent coin listing from CoinArchives gives the same reverse legend and attribution:

• "LEG V MAC VI P VI F"
• "Legio V Macedonica"

So the article's caption is wrong in two ways: it writes VII instead of V in the legend, and it calls the legion Legio VII Macedonica instead of Legio V Macedonica.

The date in this sentence is off by a year.

Modern historical summaries date Valerian's capture by Shapur at Edessa to 260 CE, not 259:

• World History Encyclopedia states that Valerian ruled "until his capture in 260 CE" and says that at the Battle of Edessa, "In 260 CE ... Valerian met with Shapur ... [and] the meeting turned into a trap."
• A standard reference text reproduced at Wikisource likewise says Gallienus reigned jointly with Valerian from 253 to 260, and that Valerian was taken prisoner "in 260."

The Christian evidence also places Gallienus's peace measure after Valerian's fall in autumn 260, not after a capture in 259. The CCEL edition of Dionysius of Alexandria says: "The persecution lasted till the autumn of 260, and was then, on the disappearance of Valerian, stayed by an edict of Peace issued by his son Gallienus."

So the article's phrase "the year 259" is not consistent with the standard dating of Valerian's capture or with the usual dating of Gallienus's toleration policy.

The problem here is terminological and substantive.

Gallienus is commonly credited with creating a mobile cavalry corps or "battlecavalry". But the comitatenses were a later category of late Roman field-army troops, not Gallienus's own primarily cavalry force.

Evidence:

• A Durham University thesis specifically on Gallienus's reforms says his cavalry reform created a powerful body of cavalry, but that this "battlecavalry" was not the direct ancestor of the later comitatenses.
• A modern overview of the late Roman army explains that by the 4th century CE there were different kinds of legions, including "Comitatenses or field armies", and describes them as field forces that included mixed troop types; it separately discusses cavalry units.
• A general history of Gallienus from the same reference work describes his reform as the creation of "a cavalry corps of armored horsemen", not as the creation of the comitatenses.

So the article's wording is inaccurate because it identifies Gallienus's cavalry corps as the Comitatenses, when those are a later and broader field-army classification.