It struck me that Anatolia and Middle East had a remarkably little population (at least in early-modern period and beyond) before experiencing high population growth in 20th century . For example in early 19th century, the population of entire Ottoman Empire, from Balkans to Egypt, was comparable to France or Germany (which had been ravaged in Thirty Years’ War, as far as I know), despite having a much bigger landmass, even if barren areas such as deserts are excluded. Iran wasn’t any better either, it had significantly less population compared to Italy or Spain. Why was that? Invasions? Disease? Agriculture? Was it like that since antiquity, or say since early middle ages? Any good books or articles etc. that are specifically about this subject (or that have a good deal of information about this subject) ?