Alexis Tsipras was sworn in as the new Prime Minister of Greece, after his radical left-wing movement forged an unwieldy alliance with a far-right party.
In a low-key ceremony lasting barely 10 minutes, Tsipras promised to protect "the interests of the Greek people" as he signed an official mandate with a Mont Blanc fountain pen.
Well known for his disdain of ties, he arrived in an open-necked shirt.
He then went on to the National Resistance Memorial at Kaisariani and laid a wreath to 200 Greek war dead as his first official act.
In a further break with convention, Tsipras, an atheist, chose not to receive a blessing from the Greek Orthodox Church, becoming the first Prime Minister in the modern Greek state to reject the religious gesture.
Tsipras's party, Syriza, scored a historic victory in Greece's election but fell short of an outright majority in the 300-seat Parliament, gaining 149 seats. While he moved quickly to arrange an awkward coalition with the Independent Greeks party, who won 13 seats, it immediately raised doubts over the longevity of the new Government.
The only common ground between the two parties is their resentment of the austerity policies foisted on Greece for the past five years by the EU and International Monetary Fund (IMF) and their determination to renegotiate the country's 240 billion ($363 billion) debt.
The parties admitted that they had profound differences. "Let us not beat about the bush, we are chalk and cheese," said Yanis Varoufakis, an economist from Syriza who is tipped to be the new Finance Minister. "It is a very strange alliance," said Vassilis Kostoulas, economics editor of Naftemporiki, a business newspaper.
"The only common characteristic between them is their opposition to the bailout. The rest, it will be chaos."
Tsipras struck the deal with Panos Kammenos, the head of the Independent Greeks, on his way to the presidential palace in Athens to be sworn in. "We have an uphill road ahead," he said to Karolos Papoulias, the Greek President.