As the grouping of the rooms upon the ground floor made the house less compact and more susceptible to successful attack, the custom arose of having upper chambers. The upper room was called the solar, because it received much light from the sun. At first it was but a small chamber, approached from the outside. These outer stairs are often referred to in the _fabliaux_, as in the _fabliau_ of D'Estourmi, where a burgher and his wife deceive three monks of a neighboring abbey, who make love to the lady; she conceals her husband in the upper chamber, to which he goes by an outer staircase. The monks enter the hall, and the husband sees from the upper room, through a lattice, all that happens. In another _fabliau_, a lady uses the solar as a hiding place for her husband, who has disguised himself as a gallant in order to test his wife's faithfulness. She penetrates his disguise, and, after closing the door of the solar upon him, sends a servant to give him a good beating, as an importunate suitor whom she desires to cure of his annoying passion. The husband, too mortified to reveal his identity and disclose his doubts as to his wife, has no redress but to sustain his assumed character and to escape down the outer stairs, pursued by the servants. The chamber soon came to be the most important part of the house, and frequently its name was given to the whole dwelling, a house with a solar being called an upper-storied chamber. The more considerable manors and castles differed from the ordinary houses only in having a greater assemblage of rooms and more details than were found in the smaller dwellings.