Both Saudi Arabia and Qatar mediated through the GCC during the Yemeni Revolution against President Ali Abdullah Saleh, although Qatar was considered more pro-revolution and KSA more pro-Saleh. Both rivals also backed the overthrow of Syrian President Bashar al-Assad, a key ally of Iran and its Lebanese proxy Hezbollah. Qatari involvement in the Syrian Civil War was initially far greater in 2013 than Saudi involvement, and their backing of rival revolutionary groups benefited the incumbent government of Bashar al-Assad and what would become the Islamic State of Iraq and Syria. In 2014, the two countries backed rival sides in the Second Libyan Civil War, which continues to intensify, and they had even temporarily severed diplomatic relations with each other. When Salman of Saudi Arabia ascended to the throne in 2015, the two began to cooperate more in Syria and fought alleged Houthi militias in the Yemeni Civil War. Relations were seen at near a high point when Qatar severed relations with Iran following the 2016 Saudi execution of Nimr al-Nimr.