An Eruv map from Szombathely (before 1945)

According to Jewish religious rules, Saturday, the Shabbat is a day of rest when no labor can be performed whatsoever. Nothing can be moved or carried, except personal items (keys, prayer book, baby carriage, etc.) which can be moved within the perimeters of the house or the yard. These items however are necessary to perform Shabbat activities, and among them the service in the synagogue. For this reason, communities often declare the entire area of the Jewish quarter one single household, this is called the Eruv. The perimeter of the Eruv is often signaled by a tightened rope around the area within which these objects can be freely carried around and moved. This way, people can go to the synagogue and adhere to the rules of the Shabbat at the same time.