Why did some of these humble settlements develop into cities while others remained small? Is it set in stone that the largest cities remain large or can large catastrophes lead a city's development astray while others arise? And can policies that target improvements in a city's centuries old transport infrastructure help to ease the higher demand for inner city transportation in a more urbanized and motorized world? In three empirical chapters, this thesis uses and introduces novel approaches that tackle methodological challenges surrounding these and more questions on the "Historical Roots of Cities".In chapter 2, we look at the landscape of settlements during the early Middle Ages around today's Germany and beyond, as most of today's citi...