There are several versions that explain origin of the Czech Republic flag colors. One of the legends say that Duke Lech once saw white eagle on the red evening sky, so he decided to adopt it on the flag.
The Czech Republic flag colors are borrowed from the coat of arms of Bohemia. The blue triangle was added to the Czech flag in 1920 in order to differentiate it from the flag of Poland. It is said that the blue color is representing the State of Moravia.
There is an important symbolic meaning behind the colors of the Czech flag. The white color stands for the people of the Czech Republic and their peaceful nature and honesty. Red color means courage, valor and patriotism of the nation. The blue symbolizes vigilance, truth, loyalty and perseverance.