For 5000 years sourdough was used for all types of bread. But when baker’s yeast appeared in the bakery some 150 years ago, bakers started to forget how to make sourdough. This was because using baker's yeast meant fermentation was quicker and more consistent.
Today, sourdough can be used in any type of bread, depending on the application and the flavour profile the baker is looking for.
For example :