Creating a pit cellar in clay soil

I am interested in medieval construction techniques and would like to create a pit cellar in my garden. I have already dug the pit, but despite the heavily clayey soil, water is seeping from the ground into the cellar. How does one seal something like this with simple, authentic means?

You cannot prevent water ingress with simple means; in modern construction, the basement wall is sealed from the outside, but you will not be able to make a pit watertight, I think the groundwater is too high there for your purposes.

We have also created a so-called pit cellar under our equipment shed. For me, the best way to create a usable cellar for wine, beer, and vegetables. What exact problem do you have? I assume the cellar is not finished yet?

I am just going to write something together since we also have a damp clay soil. As soon as you start digging, water collects in the pit. This is because the pressure in the pit is suddenly lower than the pressure in the soil. The damp clay releases its water, but this is not groundwater. The question is what should the basement look like? Should the walls be masonry? What does the foundation look like?

So we are currently having our house built by the company Lindemann-Gruppe and our shell is already standing. However, we will probably have to wait until next year for it to be "turnkey". I think, in general, you can't really say that..Trial and error ;)