Short answers, pulled from the story.
The dome was completed in 1436. This engineering feat elevated the architect from a mere craftsman to a visionary intellectual and defined the profession for the next six hundred years.
Vitruvius argued that a good building must embody firmness, commodity, and delight. These concepts translate to durability, utility, and beauty and became the enduring triad of architectural theory.
The Bauhaus school was founded in Weimar, Germany in 1919. It redefined architectural bounds by viewing building creation as the ultimate synthesis of art, craft, and technology.
Robert Venturi famously defined postmodern architecture as a decorated shed. He described it as an ordinary building which is functionally designed inside and embellished on the outside.
The U.S. Green Building Council's LEED rating system has been influential in sustainable building design. It works alongside other energy efficiency and green building rating systems like Energy Star and Green Globes.