Sebastiano Serlio in the context of Giacomo Barozzi da Vignola

Classical architecture typically refers to architecture consciously derived from the principles of Greek and Roman architecture of classical antiquity, or more specifically, from De architectura (c. 10 AD) by the Roman architect Vitruvius. Variations of classical architecture have arguably existed since the Carolingian Renaissance, and became especially prominent during the Italian Renaissance and the later period known as neoclassical architecture or Classical revival. While classical styles of architecture can vary, they generally share a common "vocabulary" of decorative and structural elements. Across much of the Western world, classical architectural styles have dominated the history of architecture from the Renaissance until World War II. Classical architecture continues to influence contemporary architects.

The term classical architecture can also refer to any architectural tradition that has evolved to a highly refined form, such as classical Chinese or Mayan architecture. It may also describe architecture that adheres to classical aesthetic philosophy. The term might be used differently from "traditional" or "vernacular architecture", it can share underlying axioms with it.

The Tuscan order (Latin Ordo Tuscanicus or Ordo Tuscanus, with the meaning of Etruscan order) is one of the two classical orders developed by the Romans, the other being the composite order. It is influenced by the Doric order, but with un-fluted columns and a simpler entablature with no triglyphs or guttae. While relatively simple columns with round capitals had been part of the vernacular architecture of Italy and much of Europe since at least Etruscan architecture, the Romans did not consider this style to be a distinct architectural order (for example, the Roman architect Vitruvius did not include it alongside his descriptions of the Greek Doric, Ionic, and Corinthian orders). Its classification as a separate formal order is first mentioned in Isidore of Seville's 6th-century Etymologiae and refined during the Italian Renaissance.

Sebastiano Serlio described five orders including a "Tuscan order", "the solidest and least ornate", in his fourth book of Regole generali di architettura sopra le cinque maniere de gli edifici (1537). Though Fra Giocondo had attempted a first illustration of a Tuscan capital in his printed edition of Vitruvius (1511), he showed the capital with an egg and dart enrichment that belonged to the Ionic. The "most rustic" Tuscan order of Serlio was later carefully delineated by Andrea Palladio.

Giacomo Barozzi da Vignola (UK: /vɪnˈjoʊlə/ vin-YOH-lə, US: /viːnˈ-/ veen-, Italian: [ˈdʒaːkomo baˈrɔttsi da (v)viɲˈɲɔːla]; 1 October 1507 – 7 July 1573), often simply called Vignola, was one of the great Italian architects of 16th century Mannerism. His two great masterpieces are the Villa Farnese at Caprarola and the Jesuits' Church of the Gesù in Rome. The three architects who spread the Italian Renaissance style throughout Western Europe are Vignola, Serlio and Palladio. He is often considered the most important architect in Rome in the Mannerist era.