Numerous events beginning in the second decade of the 18th century, when English tourists began to visit Italy to experience, explore, and collect fragments of its antique past, herald this new and increasing interest in archaeology. As early as 1719, Bernard de Montfaucon, a French antiquarian, began to publish his 10-volume Antiquité expliquée. It was an immediate success. Excavations at the newly discovered ancient cities of Pompeii and Herculaneum (discovered in 1719) began in 1748 and 1738, respectively. The publication of the Comte de Caylus's Recueil d'antiquités, which began to appear in 1752, was another landmark. Influential plates of Roman antiquities drawn by Giovanni Battista Piranesi first appeared in 1743, the year of publication of the Prima parte di architettura. A steady stream of similar works followed from Piranesi's workshop, among them the Antichità romane (1748), the Carceri (c. 1745), Della magnificenza ed architettura de' Romani (1761), and the Parere su l'architettura (1764). The first of a long and significant list of publications of measured drawings and picturesque views of Roman and Greek antiquities was Robert Wood's Ruins of Palmyra (1753), which was followed in 1757 by the same author's Ruins of Balbec and by the Ruins of the Palace of the Emperor Diocletian at Spalatro in Dalmatia, written in 1764 by the English Neoclassical architect and designer Robert Adam.

At the same time a significant interest in Greek antiquities was emerging along with a growing belief in the superiority of Greek over Roman that was to result in a Greek Revival in architecture. At about this time the 6th-century Greek ruins at Paestum in southern Italy and in Sicily began to attract the attention of visitors. The Paestum sites were first described by the Italian artist Domenico Antonini in 1745. In 1750 the French architect Jacques-Gabriel Soufflot visited Paestum. The following year Giuseppe Maria Pancrazi's Antichità siciliane appeared, and in 1769 the architect Gabriel-Pierre-Martin Dumont's Ruines de Paestum was published. The picturesque qualities of these Greek temples, with their heavy baseless columns broken and overgrown with romantic vegetation, prompted those interested in architecture to venture farther afield and to explore the Greek mainland and Asia Minor. The first book with detailed illustrations of Greek monuments to be published was the Frenchman Julien-David LeRoy's Ruines des plus beaux monuments de la Grèce (1758). This was followed by The Antiquities of Athens by two English architects, James Stuart and Nicholas Revett, which appeared in three parts in 1762, 1789, and 1795.

The pursuit of Greek architecture had as one incentive the pursuit of primitive truth and thus of an inherent rationalism. This line of thought had been developed early in the 18th century and was popularized by a French Jesuit, Marc-Antoine Laugier, whose Essai sur l'architecture appeared in French in 1753 and in English in 1755. Advocating a return to rationalism and simplicity in building and taking the primitive hut as his example of the fundamental expression of human needs, Laugier was both reacting against the excesses of the Rococo period and laying the theoretical groundwork for Neoclassicism. He did not advocate copying Greek forms, with which he was probably unacquainted, but argued that all forms not having a structural or functional purpose should be eliminated. The actual imitation of Greek architecture developed slowly, though the idea of the superiority of Greek over Roman architecture was established by Johann Joachim Winckelmann's Gedanken über die Nachahmung der griechischen Werke in der Malerei und Bildhauerkunst (1755; Reflections on the Painting and Sculpture of the Greeks).

The centre of international Neoclassicism was Rome, a gathering place, from the 1740s on, for talented young artists from all over Europe. Virtually every figure who was to play a significant role in the movement passed through that city.   Although it was Rome, the cradle of Italian antiquities, that provided the stage, the leading actors in the Neoclassical drama were French, German, or English; very little was contributed by Italians to this new movement. The centre of activity was the French Academy, where winners of the academy's coveted Prix de Rome went to study the monuments firsthand and to be exposed to the artistic life of the Italian capital. The projects produced by French Prix de Rome winners are characterized by their grandeur of scale; strict geometric organization; simplicity of geometric forms; Greek or Roman detail; dramatic use of columns, particularly to articulate interior spaces and create urban landscapes; and a preference for blank walls and the contrast of formal volumes and textures. The same qualities describe Neoclassical architecture as it was to emerge throughout Europe and in America.