(Reuters) - An agreement to end a four-month political crisis in Honduras collapsed early on Friday after two rival leaders failed to form a unity cabinet to heal the damage from a June coup.

Here is a timeline of events since the crisis began:

June 24 - President Manuel Zelaya fires military chief of staff after the army refused to help distribute ballots for an unofficial referendum on overhauling the constitution. Critics said the vote was a veiled attempt by Zelaya to allow for his re-election, a charge he denies.

June 25 - The Supreme Court orders army chief reinstated. Zelaya leads a group of rowdy supporters to storm a military base to take ballots by force.

June 28 - On the day of the referendum vote, soldiers stage a coup by arresting Zelaya in an early-morning raid on his house and, while he's still in pajamas, exile him to Costa Rica.

-- Congress names Roberto Micheletti interim president.

-- International lenders suspend loans to Honduras.

June 29 - U.S. President Barack Obama says the coup is illegal and will set a "terrible precedent."

July 4 - The Organization of American States, or OAS, meets in Washington and suspends Honduras.

July 5 - At least one pro-Zelaya protester is killed in clashes at Tegucigalpa's airport as Honduran troops block an attempt by Zelaya to fly home.

July 8 - The United States suspends $16.5 million in aid.

July 9 - Micheletti and Zelaya speak to Costa Rican President Oscar Arias to discuss the crisis but never meet one another face-to-face. Envoys draft an agreement after days of talks but it's rejected over the issue of Zelaya's return.

Sept 21 - Zelaya ends almost three months of exile by sneaking back into Honduras, where he seeks refuge at the Brazilian embassy to avoid arrest. Soldiers patrol streets around the embassy and enforce an all-day curfew.

Set 27 - Micheletti issues a decree that curbs civil liberties by shutting down pro-Zelaya news channels and banning protests. It remains in place for two weeks.

Oct 7 - Envoys of Zelaya and Micheletti begin new talks but the dialogue will soon collapse again.

Oct 29 - A high-level U.S. delegation pressures both sides to sign a deal that leaves the question of Zelaya's return up to Congress and an opinion by the Supreme Court.

Nov 6 - The agreement crumbles after Congress stalls and Zelaya, still holed up in the Brazilian Embassy, says Micheletti moved to form a new government without him. He calls on Hondurans to boycott the presidential elections on November 29.

(Writing by David Cutler, London Editorial Reference Unit and Mica Rosenberg in Mexico City; editing by Philip Barbara)