Decline

Rampant inflation, border incursions and manpower shortages during the third century CE led to increasing military demands on the Imperial purse, from which the Empire never quite recovered. For lesser magistrates, the obligatory munera became an increasingly unrewarding tax on the doubtful privileges of office but the decline of the munus was not a straightforward process. Emperors continued to subsidize their performance as a matter of undiminished public interest. In the early 3rd century CE, the Christian writer Tertullian had acknowledged their power over the Christian flock, and was compelled to be blunt: the combats were murder, their witnessing spiritually and morally harmful and the gladiator an instrument of pagan human sacrifice. In the next century, Augustine deplored the youthful fascination of his friend (and later fellow-convert and Bishop) Alypius, with the munera spectacle as inimical to a Christian life and salvation. Amphitheatres continued to host the spectacular administration of Imperial justice: in 315 CE Constantine I condemned child-snatchers ad bestias in the arena. Ten years later, he banned the gladiator munera:

In times in which peace and peace relating to domestic affairs prevail bloody demonstrations displease us. Therefore, we order that there may be no more gladiator combats. Those who were condemned to become gladiators for their crimes are to work from now on in the mines. Thus they pay for their crimes without having to pour their blood.

A 5th century CE mosaic in the Great Palace of Constantinople depicts two venatores fighting a tiger.

An Imperially sanctioned munus at some time in the 330s CE suggests that yet again, Imperial legislation was ineffective, not least when Constantine defied his own law. In 365 CE Valentinian I threatened to fine a judge who sentenced Christians to the arena and in 384, attempted to limit the expenses of munera. In 393 CE Theodosius adopted Christianity as the Roman state religion and banned pagan festivals. The ludi continued, very gradually shorn of their stubbornly pagan munera. Honorius legally ended munera in 399 CE, and again in 404 CE, at least in the Western half of the Empire – according to Theodoret because of the martyrdom of Saint Telemachus by spectators at a munus. Valentinian III repeated the ban in 438CE, perhaps effectively, though venationes continued beyond 536 CE.
It is not known how many gladiatoria munera were given throughout the Roman period. Many – if not most – involved venationes, and in the later Empire some may have been only that. One primary source, the Calendar of Furius Dionysius Philocalus for 354 CE, survives to suggest how the gladiator featured among a multitude of festivals in the Late Empire period. In that year, 176 days were reserved for spectacles of various kinds. Of these, 102 days were for theatrical shows, 64 for chariot races and just 10 in December for gladiator games and venationes. Thomas Wiedemann interprets this in the much earlier context of the Historia Augusta, in which Alexander Severus (reigned 222–235 CE) was said to intend the redistribution of munera throughout the year. This would have broken with the traditional positioning of the major gladiator games at the year's end: as Wiedemann points out, December was the month for Saturnalia, the festival in which the lowest became the highest, and in which death was linked to renewal.