The flag of Naples used to be blue, yellow, and red as a part of the Parthenopaean Republic before it was turned into its current color (blue, black, and red).
When Naples was part of the Parthenopaean Republic (1799), the flag had 3 vertical zones, blue, yellow and red. After 1806, the flag was split horizontally in white, red and black. Both horizontal and vertical versions were in use. This flag was used up to 1808. From 1820 through 1821, the flag of Naples had 3 horizontal zones colored blue, black and red. The current flag has been in use since 1821. 
