اتحاد الجمهوريات العربية
In the 1950s, a sub-set of the Pan-Arab colours, the Arab Liberation colours, came to prominence. These consist of a tricolour of red, white and black bands, with green given less prominence or not included. The Arab Liberation tricolour was inspired by the use of the "Arab Liberation Flag" in the Egyptian Revolution of 1952. This became the basis for the current flags of Egypt, Iraq, Sudan, Syria, and Yemen (and formerly in the flags of the rival states of North Yemen and South Yemen), and in the short-lived Arab unions of the United Arab Republic and the Federation of Arab Republics.