In 1848, when the ethnic groups'independence movement intensified during the mid 19th century while still under the control of the Russian Empire, the yellow and blue horizontally divided flag was chosen as the Ukrainian ethnic groups' flag. The two colors were ones used in heraldic emblems and flags from old times. Some say that blue represents the sky, and yellow, the ripened wheat, while others say that blue represents water, and yellow represents fire, but there is no official explanation. In 1992, when the nation attained independence, the flag was made official.