Created in around 1425 -1452 CE in Florence, Italy, this pair of doors graces the eastern entrance of the Baptistry, which was built around 1050 CE. Many don't know that the doors that presently featured on the Baptistry are copies. The original panels are in the Duomo Museum for safekeeping and are currently being restored.
Here is a collection of the original panels. As you can see, the gold gilt that was overlaid on top of brass shows the damage of peeling, cracking and subsequent oxidation. Part of the restoration efforts focus on removing the oxidation and repairing the gilt on these amazing and profound reliefs.
Interestingly, it was Michaelangelo who first referred to them as "The Gates of Paradise".