Oromia is the homeland of the Oromo people who have their own unique culture, history, and language. The Gadaa system was a traditional system of social stratification and governance for Oromo males, dividing society into classes that progressed through grades over an eight-year cycle. Irreechaa is a thanksgiving festival celebrated by Oromos at the end of the rainy winter season to welcome the new season and thank God for blessings. The Oromo Liberation Front was established in 1973 to promote self-determination for Oromos against Amhara domination and oppression of Oromo people and culture.