In Lebanon, political leadership and representation are officially divided up according to religious affiliation. This system, confessionalism, is supposed to encourage peace and cooperation between disparate faiths.
The original agreement (known as the National Pact) was set in 1943. The president and army commander would always be Catholic; the deputy prime minister and deputy speaker would always be Greek Orthodox Christian; and Christians would have 54 of the 99 seats in parliament. The prime minister would always be Sunni Muslim; the parliamentary speaker would always be Shia Muslim; and 45 of the 99 seats were theirs (although this total also included the Druze, who I will write about another time).
This institutional lean towards the Christian inhabitants of Lebanon contributed to a long civil war, from 1975 until 1990. At the conclusion of that war, the Taif Agreement redrew the political boundaries so that Christian and Muslim inhabitants had equal representation in parliament.