History of Sudan
The modern Republic of Sudan was formed in 1956 and inherited its boundaries from Anglo-Egyptian Sudan, established in 1899. For times predating 1899, usage of the term "Sudan" for the territory of the Republic of Sudan was somewhat anachronistic, and may have referred to the more diffuse concept of the Sudan.
Flag of Sudan
Upon independence from Egypt and the United Kingdom on 1 January 1956, Sudan adopted a blue-yellow-green tricolour as its national flag. This flag remained in use until 1970, when the current flag was adopted. The colours of the flag represented the River Nile (blue), the Sahara (yellow) and farmlands (green). They were chosen as they were neutral between ethnic groups and political parties.