No one doubts the convenience and indeed necessity of historical periodizations. Nor the validity and usefulness of well-established categories: (Late) Antiquity, the early Middle Ages, Byzantium/East Rome, Sasanid Iran, early Islam.
We can be sure that, when Alois Riegl invented Late Antiquity in his "Spätrömische Kunstindustrie" (1901), his famous study of late Roman art, he could never have imagined how fertile his proposal for evaluating the late antique as an autonomous phase in the history of artand for rejecting the concept of decadence and declinewould be.
Although an outdated, isolationist approach to Late Antiquity primarily focusing on late Roman culture and society still dominates some quarters of the academy, many scholars have worked towards a more integrated and comparative approach to the period. The shifts have been gradual and partial. Today there are numerous scholars of rabbinics who explore the wider context of the Babylonian Talmud in Sasanian society; there has lately been a resurgence of interest in the history of the Red Sea region, including Ethiopia and the Yemen, in the centuries leading up to the rise of Islam; and over the last ten years or so, we have seen significant interest in the literary and religious parallels to the Quran found in Syriac Christian literature in particular.
The various cultures and literatures of Late Antiquity cannot be viewed in isolation but rather must be approached in the wider context of the dynamic exchanges between various communities in the period, the imperial competition between the Romans and the Sasanians, and the spread and consolidation of the monotheistic or Abrahamic traditions.