Cum ad regiones caeli ita ea fuerint disposita, tunc etiam animadvertendum est, quibus rationibus privatis aedificiis propria loca patribus familiarum et quemadmodum communia cum extraneis aedificari debeant. namque ex his quae propria sunt, in ea non est potestas omnibus intro eundi nisi invitatis, quemadmodum sunt cubicula, triclinia, balneae ceteraque, quae easdem habent usus rationes. communia autem sunt, quibus etiam invocati suo iure de populo possunt venire, id est vestibula, cava aedium, peristylia, quaeque eundem habere possunt usum. igitur is, qui communi sunt fortuna, non necessaria magnifica vestibula nec tabulina neque atria, quod in aliis officia praestant ambiundo neque ab aliis ambiuntur. qui autem fructibus rusticis serviunt, in eorum vestibulis stabula, tabernae, in aedibus cryptae, horrea, apothecae ceteraque, quae ad fructus servandos magis quam ad elegantiae decorem possunt esse, ita sunt facienda. Item feneratoribus et publicanis commodiora et speciosiora et ab insidiis tuta, forensibus autem et disertis elegantiora et spatiosiora ad conventos excipiundos, nobilibus vero, qui honores magistratusque gerundo praestare debent officia civibus, faciunda sunt vestibula regalia alta, atria et peristylia amplissima, silvae ambulationesque laxiores ad decorem maiestatis perfectae; praeterea bibliothecas, basilicas non dissimili modo quam publicorum operum magnificentia comparatas, quod in domibus eorum saepius et publica consilia et privata iudicia arbitriaque conficiuntur.
(Vitruvius, Arch. 6.5.1-2)
After settling the positions of the rooms with regard to the quarters of the sky, we must next consider the principles on which should be constructed those apartments in private houses which are meant for the householders themselves, and those which are to be shared in common with outsiders. The private rooms are those into which nobody has the right to enter without an invitation, such as bedrooms, dining rooms, bathrooms, and all others used for the like purposes. The common are those which any of the people have a perfect right to enter, even without an invitation: that is, entrance courts, cavaedia, peristyles, and all intended for the like purpose. Hence, men of everyday fortune do not need entrance courts, tablina, or atriums built in grand style, because such men are more apt to discharge their social obligations by going round to others than to have others come to them. Those who do business in country produce must have stalls and shops in their entrance courts, with crypts, granaries, storerooms, and so forth in their houses, constructed more for the purpose of keeping the produce in good condition than for ornamental beauty. For capitalists and farmers of the revenue, somewhat comfortable and showy apartments must be constructed, secure against robbery; for advocates and public speakers, handsomer and more roomy, to accommodate meetings; for men of rank who, from holding offices and magistracies, have social obligations to their fellow-citizens, lofty entrance courts in regal style, and most spacious atriums and peristyles, with plantations and walks of some extent in them, appropriate to their dignity. They need also libraries, picture galleries, and basilicas, finished in a style similar to that of great public buildings, since public councils as well as private law suits and hearings before arbitrators are very often held in the houses of such men. (tr. Morris Hicky Morgan)