Although no specific person has ever been credited with the invention of glass windows, the first known use of glass in windows was during the Roman Empire. This likely occurred in about 100 C.E. in Roman-occupied Alexandria.
While crude glass windows were found many places in the Roman Empire, Alexandria was one of the centers for glass production and the place where glassblowing was invented. The technical advances made there allowed glass windows to be used, although they were still lumpy and much darker than modern glass windows. Glass became more advanced during the second and third centuries, but, with the exception of stained glass in cathedrals and castles, glass became less prevalent after the fall of the Roman Empire.