El Salvador Flag: Meaning and History

History of the flag
El Salvador was under Spanish rule until 1531 and under the Mexican Empire until 1821.
The country changed its flag several times but has always used the colors blue and white. The current flag dates back to 1921.
What do the elements of the flag mean?

The central coat of arms features three volcanoes by the ocean, surrounded by a yellow triangle with a Phrygian cap representing liberty.
The top blue stripe represents the sky, while the bottom blue stripe represents the ocean.
The central white stripe represents peace.
