It damaged Sudan's economy and led to food shortages, resulting in starvation and malnutrition. The lack of investment during this time, particularly in the south, meant a generation lost access to basic health services, education, and jobs. It is important to distinguish the Sudanic Arab from other Arabs of the middle east. Sudanic Arabs are descended primarily from the ancient Nubians. In terms of racial origin, it is not clear what specific racial or ethnic group the Nubians originated from. Over a period of centuries, Arab immigration into the Sudan, intermarriage among Nubians and Arabs, and the introduction of Islam and the Arabic language, Arabized the Nubians into the Sudanic Arab of today. In appearance, the Nubians are similar to some Ethiopians and Eritreans; at one point, they shared a common history with the latter (See ancient Kush, and Axum). The Sudanic Arabs are further divided into many different tribes of Nubian or Arab origin, and some Sudanese speak a Nubian language as a mother tongue, and Arabic as a second language. This process of Arabization was repeated throughout North Africa and the Middle East, i.e., in Libya, where the indigenous Berbers and conquering Arabs merged to form the modern Libyan Arab, as distinguished from the Persians of Iran, who accepted Islam, but rejected Arabic, and an Arab identity. Peace talks between the southern rebels and the government made substantial progress in 2003 and early 2004. The peace was consolidated with the official signing by both sides of the Nairobi Comprehensive Peace Agreement 9 January 2005, granting Southern Sudan autonomy for six years, to be followed by a referendum about independence. It created a co-vice president position and allowed the north and south to split oil equally, but also left both the North's and South's armies in place. John Garang, the south's elected co-vice president died in a helicopter crash on August 1, 2005, three weeks after being sworn in. This resulted in riots, but the peace was eventually able to continue. The United Nations Mission in Sudan (UNMIS) was established under UN Security Council Resolution 1590 of March 24, 2005. Its mandate is to support implementation of the Comprehensive Peace Agreement, and to perform functions relating to humanitarian assistance, and protection and promotion of human rights.