The first opera houses were built in the 1630s in Italy, about thirty years after the first operas were written. Traditionally they have a stage where the action takes place and a proscenium archway with a curtain that can be drawn back when the performance begins. In front of the stage is an orchestra pit which is a little lower than the stage so that the audience can still see the stage. The audience sit in the auditorium which is often horse-shoe shaped. The downstairs seats are called “stalls”. Round the stalls there are two or three tiers (storeys) of boxes. Each box can seat a small number of people. At the top towards the back there is a balcony and often a gallery along the sides as well. Some seats in the gallery may have restricted view (it is not possible to see all of the stage).