Portuguese vexillology

Portuguese vexillology is the use of flags in Portugal. It originates from the early battle standards of medieval Portugal.

Characteristics
In relation to subnational flags, the rules are: gyronny or smooth field bearing coat of arms with five towers on the mural crown if the municipality or parish is headquartered in a city (cidade), quarterd or smooth field bearing coat of arms with four towers on the mural crown if the municipality or parish is based in a town (vila), and quartered or smooth field bearing coat of arms with three towers on the mural crown if it is a municipality based in a village (aldeia) or is an urban neighborhood of a town or city.

Also in accordance with the Portuguese heraldry, flags can be divided octagonally, hexagonally, quarterly in saltire, cross or belt and still having the same color-field constants of the shield and the center estentendo stuff or a geometric figure where the coat of arms is applied.