What was once a marriage of convenience has become a bitter and damaging fight between two men that threatens to damage Turkish democracy and change its face forever.
When a group within Turkeys military launched a coup on Friday night, Recep Tayyip Erdogan wasted little time in blaming Fethullah Gulen and his followers, which he describes as a terrorist organisation.
Gulen, an Islamic preacher and former imam, is the spiritual leader of the moderate Islamic Hizmet movement that spans dozens of countries. He has firmly denied any involvement.
His soft power in Turkey with thousands of followers, often called Gulenists by their opponents, offered Erdogan a base of supporters during the early years of his premiership from 2003.
The two men's divorce in 2013 is often blamed on Erdogans efforts to reconcile with the Kurds in the south-east and his crackdown on the schools run by the movement called dershanes where students get extra help to pass the university entrance exam.
The authorites detested the Gulen-run school system, fearing it was creating thousands of bright but loyal students who would take top positions in the police and judiciary.
They also saw Gulens hand in the 2013 protests over the Gezi Park development in Istanbul, which snowballed into anti-government demonstrations across the country.
With Erdogan now pressing the United States to extradite Gulen in the wake of the coup, their falling-out has now taken on an international dimension that could damage Washington-Ankara ties.
According to Anthony Skinner, head of political risk at Verisk Maplecroft consultancy, the two mens friendship was based on challenging the control by the then secular establishment.
The two groups wanted to weaken the military which had prior to Friday conducted three successful coups and forced the then-government out of office in 1997.
"They wanted greater control of the state. This was a burning priority for both the ruling AKP and the movement." Once in charge of the country, Skinner said there was a greater struggle for power, with the ruling Justice and Development Party (AKP) having the upper hand.
Gulenists became antagonised when AKP began to taste greater success in elections, said the analyst, especially over Erdogans rule and efforts towards forging a peace deal with the PKK (Kurdistan Worker's Party).
"We saw friction over the engagement with the PKK and the peace process," he said, noting it was the pro-Gulen press who in 2013 broke the news on secret talks between the two sides.
Gulenists at the time said they supported peace but had concerns about the approach, Skinner said.
But critics say they had concerns over the threat to their network and influence in the Kurdish southeast.The alliance unravelled in 2013 as Erdogan closed dershanes affiliated to Gulen.
But the gauntlet was really thrown down in December 2013 with a massive corruption scandal that threatened to engulf Erdogan.
Three government ministers were forced to resign over the affair which the government described as a Gulen-inspired coup attempt.
Since the investigation, the two appear to have been involved in tit-for-tat attacks with social media leaks of alleged recordings of Erdogan and allies exposing corruption within the government, which they denied vehemently.
The Erdogan government has purged thousands of officers within the police and army as well as members of the judiciary accused of having links to the preacher.
Gulen-linked media organisations were also raided in March including the Zaman newspaper and the Cihan news agency. Authorities then brought in state administrators.
Experts say there are Gulenist elements within the army but it is not possible to speculate on what links he could have to the plot.
Natalie Martin, lecturer in politics and international relations at Nottingham Trent University, asked: "Is it a Gulenist faction within the military? Possibly, but that seems a little bit too easy," she told AFP.
For Skinner, it is unlikely Gulen ordered the coup because of the risk of extradition among other issues, but said supporters within the army could have conducted the putsch on Friday.
But he too added: "It is too early to tell."