KIEV - Petro Poroshenko, who was sworn in as president of Ukraine on Saturday, is a billionaire chocolate baron whose revolutionary zeal turned him into a political comet.
The pro-Western tycoon won an outright victory in a presidential election late last month with 54.7 per cent of the votes -- a powerful mandate no one would have predicted just a year ago.
The emphatic victory was a much-needed boost for Poroshenko who takes the reins in the midst of the worst crisis between East and West since the end of the Cold War.
As if that challenge was not enough, he must also try to drag the country of 46 million out of a protracted economic recession.
"It is time for irreversible, positive change," he said after taking the oath of office in the Ukrainian parliament.
"To introduce change, we need first of all peace, security and unity."
The crisis with Russia has centred around Moscow's annexation of Crimea, a Ukrainian peninsula jutting into the Black Sea, as well as an uprising by pro-Russian rebels in the east of the country.
This pits Poroshenko against Russian President Vladimir Putin, whom he met briefly Friday as they both attended D-Day commemorations in northern France.
"The dialogue has begun, and that's a good thing," Poroshenko told Ukrainian television afterwards.
- Ukraine's Willy Wonka -
The tall, slightly greying tycoon is one of the country's 10 richest men with a fortune estimated at around $1.6 billion (1.2 billion euros) by Forbes magazine, which described him as Ukraine's Willy Wonka.
A shrewd politician who has flip-flopped between governments for more than a decade, Poroshenko was the only Ukrainian oligarch to openly back the pro-European protest movement that ousted president Viktor Yanukovych, under whom he served briefly as economics minister.
"Ukraine now returns to its natural European condition which so many generations have longed for," Poroshenko said in parliament on Saturday.
"The dictatorship that ruled Ukraine in recent years sought to deprive us of that vision, and the people rebelled."
Poroshenko was also the only politician to fly to Crimea in a bid to negotiate with pro-Russian troops who seized parliament after Yanukovych fell, but he was angrily chased off by demonstrators.
While ready to talk with Putin, he has insisted two issues are not negotiable -- Ukraine's pro-Europe direction and the status of Crimea.
"Crimea has been, is and will remain Ukrainian," he reiterated on Saturday to thunderous applause.