The Journal of Late Antiquity is now online and seems to have adopted the recent habit of annexing bits of the early Middle Ages. The journal aims to cover the late Roman, western European, Byzantine, Sassanid, and Islamic worlds, ca. AD 250800, while the existing journal Early Medieval Europe covers the history of Europe from the later Roman Empire to the eleventh century. Preferring one journal over the other is easy if you work on Egypt or Iceland, but harder otherwise. Nor is it simply about whether you think barbarians or the fall of the Roman empire are a Good Thing/Bad Thing (which is the normal cultural divide between the late antique and the early medieval). Both journals are printing articles by people like Peter Heather and Guy Halsall, after all.
The far ends of each journals period look reasonable, if youre going to stick to round numbers (rather than the spurious precision that Modern History starts in 476 AD). I suspect Peter Brown originally started late antiquity in 150 AD because that was roughly where the Oxford classics syllabus lost interest (certainly, 25 years ago, when my husband was doing classics there, they ended the history papers with the death of Trajan in 117). Either 250 or 300 AD is a good place for the start of late antiquity, depending on whether you think Diocletian or Constantine are more significant. Where the early medieval ends depends partly if youve got a central Middle Ages to go onto, or whether youre moving immediately to the later Middle Ages. But assuming youve got a middle middle, then its a choice between 1000 and mutation or 1100 with the Gregorian reforms and the Crusades, and I think Id agree with 1100 myself.
The problem is the five century overlap in the middle (300-800). It makes sense for there to be some overlap between the two periods (and the two journals), because the post-Roman world developed at a different rate. You cant really claim that fifth century Britain is late antique, but you can say that about fifth-century Gaul. On the other hand, there are some claims that are frankly unconvincing. We early medievalists ought to be thinking seriously about giving the fourth century back to the late antique people, if not in survey courses and textbooks (where you have to include some references to Constantine), at least in research terms. Equally, the attempt by late antique researchers to include the eighth century is just ridiculous. It makes no sense to cut up the two most powerful dynasties (the Carolingians and the Abbasids) in that way, and what else of late antique culture is still round by then? Id say you could either pick 600 or 700 AD as the end of late antiquity. 600 works better for western Europe (especially France and Italy), with Gregory the Great looking a very transitional figure, but 700 may make more sense for the east (and keep the Spanish historians happy). That leaves 250-400 to the late antique, 700-1100 to early medieval (both decent stretches), with three centuries in between being tugged either way, depending on your location and your field of history (roughly the early medieval comes in earlier in economic and political history and later in religious and cultural history). After all, of we could agree at least when were talking about, then maybe we could get a little further in the quest to get people thinking its worth studying things that happened before the twentieth century.