In the U.S., many homeowners, especially across the states along the U.S. Mexican border, will display the Mexican flag along with the American flag. But, what do we in the U.S. really know about the national flag of Mexico?

Mexico didn’t have an official flag until the 1820s, but the symbols you see on it are much older. They come from an ancient Aztec legend that tells of the founding of that culture’s capital city, Tenochtitlan, where Mexico City stands today.

There’s some argument as to what the colors on the Mexican flag actually represent. Some say that green stands for victory and hope, white for purity of ideal, and red for the blood of the country’s national heroes. Others say that the green stands for independence from Spain, white for the Catholic faith, and red for unity.

Under any circumstances, when flying the Mexican flag in the U.S. together with the American flag, flag etiquette dictates that the flag of another country should not be set higher than the American flag.