Thresholds (Polish mythology)
are a place that was marked a crossover between the worlds as well as home space and the outside world. It is a place to hide written spells or magical objects. It wasn’t considered acceptable to accept anything over the threshold, or to return over it once you have crossed it to start a journey. It was ill advised to cross it with the left foot first, as you would be cross into the Otherworld.
See also Polish mythology