On the left is Notre Dame de Paris, the seat of the Archbishop of Paris, and on the right is Bath Abbey, a medieval Anglican church. Both of these buildings are prime examples of Gothic architecture, characterized by tall facades, ornate stonework, and large amounts of stained glass.

Rose windows were a common feature of Gothic architecture. The rose window in Notre Dame is one of the most famous.

This church was constructed in 1436, at the height of the Gothic era of architectural construction. It cannot be the fourteenth century (1300s), as that was the Romanesque era, and churches were not being built with this kind of grandeur and detail. This is also, though, not a Renaissance building. You can tell this because the Renaissance boasted a revival of Classical Greek architecture, which is not seen here. The answer must be fifteenth century.

The window is a Rose window, a staple of Romanesque and Gothic architecture, and is very revealing of the time when it appears on a church. These were often made of stained glass, and featured intricate and delicate panes of glass that were in themselves a work of art. The Rose window always sits atop the middle door, and is sometimes flanked by smaller windows on either side. 

The Gothic building tradition is a furthering of the Romanesque, and is more intricate and detailed than Romanesque counterpart buildings. The rose windows are larger and the stained glass more intricate. There was an introduction of the King's Gallery, the row of king sculptures that sit under the rose window. And the facades grew taller and taller until Gothic churches towered over the surrounding city. What didn't change, though, was the Basilican plan. 

The main architect of the entire church was Arnolfo Di Cambio, who mastered the nave and the aisles. It was Brunelleschi, though, who pioneered the dome, which is the largest of its kind and was considered an architectural wonder of its time. He was a mathematical genius, and the dome reflected his prowess. Serving under him was the apprentice Leonardo da Vinci, who was young at the time and would go on to pioneer a number of Renaissance buildings. 

This church is Basilican, which is noteworthy for its cross-style plan, where the long nave is flanked by an aisle on either side. It is longer than it is wide, like a cross would be. The church cannot be a hall plan, as it has aisles and is not oriented in a single rectangular plan. The same is true with octagonal; the church plan does not follow the format of an eight-sided church. Cruciform churches were not popular until much later than this point. 

The church at the time had more money than the state and the wealthiest families of Italy. Likely it was the Catholic church itself that commissioned the cathedral. Given also the time it took to build, kings had come and gone and the Medici had gain and subsequently lost their prominence in Italian society, but the church was omnipresent and dominating for the three hundred years it took to go from construction to completion. 

The dome is Renaissance; it was built two hundred years after the facade of the cathedral, under the guidance of Brunelleschi and his pupil, Leonardo da Vinci. both were pioneers of the Renaissance movement. Note also the shape and nature of the dome; it is very much in the tradition of Classical Greek and later Roman temple construction styles. It is meant very much to emulate the grandeur of the Parthanon, much like the rest of the Renaissance movement emulates Roman and Greek wonders. 

A key feature of Gothic churches is their height. The supports on the sides were added to prevent structural problems. Known as "flying butresses", these supports were transformed from simple structural elements into elaborate ornamentation.