Compressed yeast didn’t being to appear until the mid nineteenth century and modern dried yeast wasn’t reliable or cheap enough for regular use until decades later. I find even recipes from 40 years ago call for more dried yeast than is necessary. As a result most of the recipes on this site use wild yeast, i.e. a sourdough starter or leaven, the same way bread has been made since the Sumerians started thirty millenia ago. The species of yeast in your starter, the flavour, strength and speed will, of course, vary – but ’twas ever thus.
Making your own sourdough starter is easy and difficult in equal measure. All you have to do is combine flour (often rye but can be wheat) and water in equal proportions (50-100 grams) and leave somewhere warm (ideally 28-30C) for a few days, ‘feeding’ it with more water and flour (around the same quantities) every day or two. If it bubbles up after about four or five days, its worked, and you can put it in the fridge. Or get some from friend or baker. Take as much as you need out of the fridge a day early and mix with the fluid in the recipe before adding to the flour.