Merkel visit marked by protests
Some 6,000 police officers were deployed for the six-hour visit, including anti-terrorist units and rooftop snipers. German sites in the Greek capital, including the embassy and Goethe Institute, were under special protection.
Before departing, Dr Merkel met Greek business people to ask how reforms were progressing and hear how they were affected by an economy that has shrunk by a fifth in five years, leaving 25 per cent of workers out of a job.
"She said: talk to me as if I wasn't a leader but a good reporter," one attendant said on condition of anonymity.
Dr Merkel decided to come to show support for Samaras, a fellow conservative, as he struggles to convince reluctant, leftist coalition partners to impose more austerity on a society fraying at the edges after several rounds of cuts.
With a year to go until Germany holds a parliamentary election, Dr Merkel also hoped to neutralise opposition criticism at home that she has neglected Greece and contributed to its woes by insisting on crushing budget cuts.
After her government flirted earlier this year with the idea of allowing Greece to exit the euro zone, she now appears determined to keep it in - at least until the German election is out of the way.
Greece is in talks with its "troika" of lenders - the European Union, European Central Bank and International Monetary Fund - on the next tranche of a €130 billion loan package, its second bailout since 2010.
Without the €31.5 billion tranche, Greece says it will run out of money by the end of November.
Dr Merkel said the aid payment was "urgently needed" but stopped short of promising that the funds would flow.
"The troika report will come when it is ready. Being thorough is more important than being quick," Dr Merkel said.
Ties between Germany and Greece run deep. Thousands of Greeks came to Germany after the second World War as "guest workers" to help rebuild the shattered country and more than 300,000 Greeks currently reside there.
But the relationship is clouded by atrocities Greeks suffered at the hands of the Nazis. Mr Samaras's own great grandmother killed herself after Nazi tanks rolled down the streets of Athens and the swastika flew over the Acropolis.
Greek president Karolos Papoulias, whom Dr Merkel also met today, fought against the Germans as a teenager, before fleeing to escape persecution by the Greek military dictatorship and finding refuge in Germany.