Shabbat 36 -- Announcing Shabbat
The communities in the time of Talmud would announce Shabbat with six blasts of the shofar. About an hour before Shabbat they would sound the first one, to top the people from performing their labor in the fields, giving them enough time to journey back to town before Shabbat. Those working in the nearby fields were not permitted to enter the town, until those who were farther away came as well. They would all enter at once, so that those working later were not suspected of working after the shofar blast. The store in the town would still be open.
At the second blast the storeowners would shutter the windows and lock the stores. At the third blast people would finish their hot food preparation and stared lighting the Shabbat candles. Then one blew another long note (tekiah), a series of short notes (teruah), and another long note. The sexton had hidden place on the top of his roof where he would leave the shofar, in order not to carry it on Shabbat.
Art: Camille Pissarro - Peasant Woman and Child Harvesting the Fields, Pontoise