Even in later times, when the houses were extended by the addition, at the rear, of a peristyle with its group of apartments, the tablinum may often have been used as a summer dining room; but the tendency now was to withdraw the family life into the more secluded rooms about the peristyle. The tablinum, lying between the front and the rear of the house, was used as a reception room for guests who were not admitted into the privacy of the home; and here undoubtedly the master of the house received his clients. In the house of the Vettii the tablinum is omitted on account of the abundance of room; but at the rear of the atrium there are wide openings into the peristyle (Fig. 158). IV. THE ALAE The alae, the 'wings' of the atrium, were two deep recesses in the sides (Fig. 115). They were ordinarily at the rear, but were sometimes placed at the middle, as in the house of Epidius Rufus (Fig. 149). Vitruvius (VI. iv. 4) says that where the atrium is from 30 to 40 feet long, one third of the length should be taken for the breadth of the alae; in the case of larger atriums the breadth of these rooms should be proportionally less, being fixed at one fifth of the length for atriums from 80 to 100 feet long; the height at the entrance should be equal to the breadth. At Pompeii the alae, as the tablinum, are narrower and higher than required by these proportions. In the Tufa Period the entrances were ornamented with pilasters, and treated like the broad entrance of the tablinum. With reference to the purpose and uses of these rooms we have no information beyond a remark of Vitruvius in regard to placing the images of ancestors in them. This throws no light upon their origin; for only a few noble families could have possessed a sufficiently large number of ancestral busts or masks to make it necessary to provide a special place for these, while the alae form an essential and characteristic part of the Pompeian house. Now and then an ala was used as a dining room; more frequently, perhaps, one was utilized for a wardrobe, as may be seen from the traces of the woodwork. A careful study of the remains only deepens the impression that at Pompeii the alae served no definite purpose, but were a survival from a previous period, in which they responded to different conditions of life. An interesting parallel presents itself in the arrangements of a type of peasants' house found in Lower Saxony. The main entrance, as in the early Italic house, leads into a large and high central room; at the sides of this and of the main entrance are the living rooms and stalls. At the back the central room is widened by two recesses corresponding with the alae; the hearth stands against the rear wall. In the side walls, at the rear of each recess, are a window and a door. The two windows admit light to the part of the central room furthest from the entrance; the doors open into the farmyard and the garden.