Sudan is poised to split into two on Sunday, with the original Sudan still under the control of Omar al-Bashir and a new South Sudan in control of about 80 percent of the region's oil reserves.

CNN reports:

Beginning Sunday, the black Christians and animists in the autonomous region of Southern Sudan will vote on whether to declare independence from the northern government dominated by Arab Muslims.

Though violence has rocked the region in days ahead of the election, the NY Times reports that officials are optimistic everything will go as planned.

The sides have been at odds for 50 years. The referendum came about because of 2005 peace deal, which ended a civil war dating back to the 1980s that killed 2 million people.

The Associated Press describes how the vote will happen:

Southern Sudanese will cast simple, illustrated ballots at polling stations under thatched-roof shelters in the remote and impoverished countryside and near newly paved roads in Juba. About 60,000 Sudanese refugees in eight other countries, including the U.S., also will cast votes.

For the referendum to pass, a simple majority must vote for independence and at least 60 percent of the nearly 4 million registered voters must cast ballots.

If the split passes as expected, the sides will have to work out revenue-sharing agreements for those oil reserves, how citizenship will work and how to split access to the West Nile River.