Portugal's results have improved enormously since Ronaldo made his international debut against Kazakhstan as an 18-year-old in 2003.
Their recent record at major tournaments is the envy of many bigger countries after they reached the Euro 2004 final, 2006 World Cup semi-finals and the Euro 2012 semi-finals, where they lost to eventual winners Spain in a shootout.
Portugal have suffered when Ronaldo, who has captained them since he was 22, has been off-form such as at the last World Cup when he suffered a bout of tendinosis in his left knee in the run-up to the competition.
The Madeira-born forward, who makes a point of breaking records, is Portugal's all-time leading scorer with 56 goals in 125 appearances and needs three more caps to beat Luis Figo's record.
Nevertheless, the three-times world player of the year has not been above criticism, with most of his goals coming in qualifying matches against weaker opponents and many supporters wondering why he did not take a penalty in the 2012 shootout against Spain.
It is, though, hard to imagine Portugal without him and Ronaldo himself says he wants to play for his country until at least the 2018 World Cup and maybe beyond.
"I don't make plans in my sporting life," he said in February. "If I feel good in three years' time, we will see what happens."
