Short Version:
Renaissance architects, builders, and artists were heavily influenced by ancient Greek and Roman art and architecture. They studied and emulated the use of proportion, symmetry, and other design principles found in ancient Greek and Roman architecture, as well as the ideals of humanism. They also found inspiration in Roman and Greek myths and legends in order to improve their own work and set the standards of beauty and harmony in art and architecture.
Long Version:
Renaissance architects, builders, and artists were heavily influenced by the art and architecture of ancient Greece and Rome. They saw the beauty and harmony in the forms and designs of ancient Greek and Roman buildings, sculptures, and other artworks. They studied and emulated the use of proportion, symmetry, and other design principles found in ancient Greek and Roman architecture.
Additionally, many Renaissance architects, builders, and artists were also inspired by the ideals of humanism, which emphasized the study of classical literature, philosophy, and art. They believed that the art and architecture of ancient Greece and Rome represented the pinnacle of human achievement and sought to emulate it in their own work.
For example, the use of columns and pediments, inspired by the Greek temples, became a common feature in Renaissance architecture, especially in the use of the Corinthian, Doric, and Ionic orders. Artists such as Raphael and Michelangelo studied ancient Roman and Greek sculptures to improve their own work and many painters like Botticelli and Jan Van Eyck found inspiration in Roman and Greek myths and legends.
In summary, the renaissance architects, builders and artists were inspired by the ancient Greek and Romans in terms of their design principles, ideals and stories which they used as a source of inspiration in their own work and helped to set the standards of beauty and harmony in the art and architecture.