CHICAGO (AFP) - From national obscurity to rewriting world history in four short years, Barack Obama has risen like a rocket to fulfil his "improbable quest" of being elected America's first black president. Fired by what he admits is a "healthy ego" and a burning self-confidence, the 47-year-old Democrat has shown not just a capacity to inspire but a shrewd cunning to first win his party's nomination and then the greatest prize itself. "It will be fun to see how the story ends," he said as he bade farewell to the travelling Press corps that have accompanied his every step across the nation and beyond over the past 21 months. One chapter of the story ended Tuesday with a mould-breaking election triumph over Republican John McCain, on a night giddy with expectation among the foot-solders of the "movement" that Obama set out to build. Another chapter now opens as he confronts the whirlwind of challenges - an economy in tumult and war on two fronts abroad - that awaits him when he succeeds President George W. Bush on January 20. The story opened on a freezing day on February 10, 2007, when the Illinois senator announced his long-odds bid for the White House outside the same state capitol building where Civil War president Abraham Lincoln once served. Lincoln, who saved the union and abolished slavery, provides the archetype for the kind of president Obama says he intends to be - and he does not shy away from linking his name to America's greatest leader. Indeed, his victory speech was marbled with references both oblique and overt to Lincoln, including his celebrated line from the Gettysburg Address about government being "of the people, by the people, for the people." Obama's speech, delivered on an electrifying night in front of more than 100,000 supporters in Chicago, came full-circle from when he urged voters to "join me in this improbable quest" when he first announced his candidacy. Obama's victory over former first lady Hillary Clinton in a bruising primary campaign full of bitter invective turned political convention on its head. The former community organiser did it by allying his dazzling oratory to a fearsome grassroots network that, against all odds, defeated the Democratic royalty of the Clinton family in both delegates and fundraising. Before they buried their differences in public, former president Bill Clinton scorned the upstart Obama and his cadre of youthful devotees. But the man now set to follow Clinton into the White House showed he had steel as well. By reversing a pledge to take public financing, Obama was able to swamp McCain with a record-breaking haul of cash that let him redraft the US political map after the last two elections' wafer-thin margins.