The ruins of baths, theatres, tombs, temple-fronts, and triumphal arches, were of little immediate assistance in the labour of designing churches and palaces.

All that the architects could do, after familiarising themselves with the remains of ancient Rome, and assimilating the spirit of Roman art, was to clothe their own inventions with classic details.

The form and structure of their edifices were modern; the parts were copied from antique models.
A want of organic unity and structural sincerity is always the result of those necessities under which a secondary and adapted style must labour; and thus the pseudo-Roman buildings even of the best Renaissance period display faults similar to those of the Italian Gothic.

While they are remarkable for grandeur of effect in all that concerns the distribution of light and shade, the covering and enclosing of space, and the disposition of masses, they show at best but a superficial correspondence between the borrowed forms and the construction these are used to mask.[28] The edifices of this period abound in more or less successful shams, in surface decoration more or less pleasing to the eye; their real greatness, meanwhile, consists in the feeling for spatial proportions and for linear harmonies possessed by their architects.
Three periods in the development of Renaissance architecture may be roughly marked.[29] The first, extending from 1420 to 1500, is the age of experiment and of luxuriant inventiveness.

The second embraces the first forty years of the sixteenth century.