The 1835 Sretenje Constitution described the colours of the Serbian flag as bright red, white and čelikasto-ugasita (that could be translated as steelish-dark). The constitution was criticized, especially by Russia, and the flag was specifically singled out as being similar to the revolutionary flag of France. Soon afterwards, Miloš Obrenović was requesting to the Porte that the new constitution should contain an article about the flag and coat of arms, and subsequent ferman (1835) allowed Serbs to use their own maritime flag, which will have "upper part of red, middle of blue, and lower of white", which is the first appearance of the colours that are used today.
The colours are the reverse of those on the flag of Russia, and various popular stories exist in Serbia which seek to explain why. An example:
“In Karađorđe's time, a delegation from Serbia went to Russia to seek help, and after arrival was at a celebration. When they were asked why don't they participate in the parade, they hastily entered and turned the Russian flag upside down. The citizens have thus noticed that Serbs have their flag too.”
Serbia used the red, blue and white tricolour continuously from 1835 until 1918 when Serbia joined the Kingdom of Serbs, Croats and Slovenes, later known as Yugoslavia.