Listen now (82 min) | I’m joined by historian and podcaster Patrick Wyman, whose “The Fall of Rome” and “Tides of History” are two of the very best historical podcasts out there, to discuss pandemic diseases in Roman history. We’re talking the Antonine Plague, the Plague of Cyprian, and the Plague of Justinian, and what they meant to the Roman Empire and (especially in the latter case) to world history in general. Later, and apropos of nothing in particular, we discuss Patrick’s
I think you are overstating how dramatic the Arabic conquest of the Sasanians was a bit. More recent views of the Sasanians (see e.g. Pourshariati) emphasise that the state was founded as a kind of confederacy between the Arsacid nobles and the House of Sasan. That collapsed during the last great war with the Byzantines, which was the immediate cause of Sasanian defeat in that war (not so much Heraclius' actions...). This institutional weakening of the Sasanians meant that they were no longer able to effectively control their Arabian client states, including the Lakhmids of southern Iraq, who had been sacking Sasanian territory before the Islamic armies came.
The Sasanians scored one decisive victory against the Arabs at the Battle of the Bridge, but it's clear that Sasanian authority was effectively fractured into a series of statelets at this point, unable to raise the grand armies that had depended on the cooperation of Arsacid nobles with the Sasanian crown. It's entirely possible that disease played a role, but the collapse of political authority in the Empire seems to be the immediate cause. Personally I suspect religious tensions between the more conservative Arsacid houses and the House of Sasan, willing to accomodate Christian vassals, played a big role during Khusrau II's attempt to, effectively, incorporate Christians into the territory, along with Khusrau Anushirwan's reforms that already created huge tensions between the nobles and the crown, along with lessening infighting for the highest posts such as Spahbed.
I think you are overstating how dramatic the Arabic conquest of the Sasanians was a bit. More recent views of the Sasanians (see e.g. Pourshariati) emphasise that the state was founded as a kind of confederacy between the Arsacid nobles and the House of Sasan. That collapsed during the last great war with the Byzantines, which was the immediate cause of Sasanian defeat in that war (not so much Heraclius' actions...). This institutional weakening of the Sasanians meant that they were no longer able to effectively control their Arabian client states, including the Lakhmids of southern Iraq, who had been sacking Sasanian territory before the Islamic armies came.
The Sasanians scored one decisive victory against the Arabs at the Battle of the Bridge, but it's clear that Sasanian authority was effectively fractured into a series of statelets at this point, unable to raise the grand armies that had depended on the cooperation of Arsacid nobles with the Sasanian crown. It's entirely possible that disease played a role, but the collapse of political authority in the Empire seems to be the immediate cause. Personally I suspect religious tensions between the more conservative Arsacid houses and the House of Sasan, willing to accomodate Christian vassals, played a big role during Khusrau II's attempt to, effectively, incorporate Christians into the territory, along with Khusrau Anushirwan's reforms that already created huge tensions between the nobles and the crown, along with lessening infighting for the highest posts such as Spahbed.