|President Lula hopes persuade Iran to reach a nuclear agreement with the West [Reuters]
November 23, 2009: Mahmoud Ahmadinejad, the Iranian president, and Luiz Inacio Lula da Silva, the Brazilian president, hold talks in Brasilia, as part of a Latin America swing that took Ahmadinejad to Bolivia and Venezuela.
After meeting with Ahmadinejad, Lula reaffirms his belief that Iran has a right to nuclear energy for peaceful purposes.
November 27: Brazil and Turkey abstain from an International Atomic Energy Agency (IAEA) vote in Vienna that would have censored Iran for its alleged secret construction of a nuclear facility in Qum.
March 3, 2010: Hillary Clinton, the US secretary of state, travels to Brazil on her Latin America tour, hoping to convince Brazil to support sanctions against Iran. The attempt is unsuccessful.
April 8: A new nuclear disarmament treaty (Start) is signed by Barack Obama, the US president, and Dimitry Medvedev, his Russian counterpart.
Medvedev signals support for the American-led drive to impose new sanctions on Iran, saying that Tehran’s nuclear programme had flouted international rules.
"We cannot turn a blind eye to this," he says, while adding that sanctions "should be smart" and avoid hardship for the Iranian people.
April 12: 47 leaders are invited to Washington for the Nuclear Security Summit. Iran is not represented.
At the end of two days of meetings, Obama issues a specific warning to Iran, saying that after four years of failed efforts on sanctions, the penalties he was trying to win at the UN Security Council had to be significant enough to get the attention of the Iranian leadership.
April 12: A line of credit was opened between Brazil and Iran's central banks.
April 19: Iran holds a nuclear summit titled "Nuclear Energy for All, Nuclear Weapons for No One".
Ahmadinejad allegedly calls on the US to destroy its own nuclear arsenal and urges that all future nuclear disarmament talks be convened by "countries like Iran, which have no nuclear weapons."
Nearly 60 countries are represented, suggesting that support for sanctions is perhaps not as widespread as the US would like.
April 26: Celso Amorim, Brazil’s foreign minister, visits Tehran, meeting with his Iranian counterpart Manuchehr Mottaki, Iran's nuclear negotiator Said Jalili, and the president of the Iranian parliament, Ali Larijani.
At the meeting, Amorim asks for assurances that Iran’s nuclear program is meant for only peaceful ends.
May 4-15: Nuclear Non-Proliferation Treaty Review Conference at the UN in New York.
The meeting, held every five years, is used partially by the US as a way to get assurances they have all five permanent security council members on board for sanctioning Iran.
But Russia and China do not give their explicit approval.
Ban Ki-moon, the UN secretary-general, urges Iran to prove that its nuclear programme is solely for peaceful purposes and to accept a compromise deal offered to Tehran last autumn. Iran had already rejected Ban's proposal last year.
May 5: Iran news agency Fars reports that Ahmadinejad agreed "in principle" to Brazilian mediation of the UN fuel-exchange deal that was proposed and fell apart.
According to the original deal, unenriched Iranian uranium would be processed in France and Russia and sent back to Iran, to be used for medical purposes.
May 14: Medvedev gives Lula a 30 per cent chance of success in his talks with Ahmadinejad.
May 16: Lula meets Ahmadinejad in Tehran, in what has been framed as possibly a last, best chance for a negotiated solution.