Hello everyone. Today we're going to tackle all your questions about Byzantium's economic

and demographic recovery. We begin with Kickstarter backer SR, who asks about the Roman road

network, such an asset in earlier centuries, allowing information and troops to travel

quickly around the Empire. How had it declined or been maintained in Byzantium, and would

it play a role in the Empire's fall? And connected to that, how did other infrastructure

investments of the earlier Empire, aqueducts, walls, trade routes, etc, help preserve the

Empire when it could no longer recreate them?

The latter part of the question takes me back to the siege of 717. It was a point that

I believe historian Mark Widow made that if the Theodosian walls had not already been

built, the Byzantines of the 8th century could never have created anything comparable from

scratch. And the land walls remain the primary answer to this question. Having visited

Istan Bulnau, I've seen first hand the difference in scale between buildings of Justinian's

day and earlier, and those that came later on. It's clear, just from looking that the

amount of money, labor, and materials needed for those earlier constructions were only

possible for a continent-wide civilization. The amount of building material needed to

raise up three separate walls across three and a half miles was enormous. Transporting

that by sea, and then dragging it across land would have been a time-consuming and expensive

operation, and then the construction itself, navigating dips and rises in the land, incorporating

a river, adding hundreds of separate towers and a moat, it just was a staggering achievement

of organization. And the manpower needed was vast, slaves, construction workers, pack

animals, engineers, soldiers, all who had to be paid, or at least fed. The cost was astronomical.

If in 717 the Byzantines had had to build fortifications to save themselves, they would

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