Old quarters in cities far apart feel oddly similar: narrow lanes, a central square, a ring road where something used to be. The resemblance comes from shared constraints rather than shared style.
The wall determined the footprint
Defensive walls were expensive to build and to man, so they enclosed as little ground as possible. Everything of value was packed inside a deliberately tight perimeter.
That pressure produced tall, narrow buildings on small plots and lanes only as wide as they needed to be. Space inside the wall was the scarce commodity.
When walls came down, the cleared ring became a boulevard, a park or a road. Many cities still show the old outline in the shape of a street that curves for no visible reason.
Water fixed the location before anything else
Settlements formed at river crossings, springs, harbours and defensible high ground near water. The site was chosen for supply and transport long before any planning existed.
Streets then radiated from the crossing point or the quay, which is why old street patterns converge on a bridge or a waterfront rather than on a geometric centre.
Where a river was later covered or a harbour silted, the pattern remains, leaving a street layout that points at something no longer there.
The market square was the functional heart
Trade needed open ground for stalls, carts and animals, and it needed to be central and controllable. The square is that space, and the important buildings face it.
A church, a town hall and a merchants' hall clustered around it because proximity to the market meant proximity to money and to the people gathering there.
Later squares were often built as extensions when the first became too small, which is why many old towns have a sequence of squares of increasing size and decreasing age.
Cart distance set the block size
Before mechanised transport, goods moved by hand or by cart, and the practical radius over which that was efficient was short. Districts formed at a walkable scale.
Streets were sized for a loaded cart to pass, not for two to pass at speed, which produces the width that now feels charming and functions poorly for cars.
Turning circles at corners explain the chamfered building edges common in old quarters, where the corner was cut back to let a cart swing through.
Fire and rebuilding standardised the details
Dense timber towns burned regularly, and the rebuilding that followed was governed by new rules on materials, height and party walls.
Those rules produced whole quarters built in a short period and to a single specification, which is why the uniform-looking historic streets are often not the oldest ones.
Reading a centre for these layers, rather than by architectural period alone, explains far more about how it feels to walk through.