The following is a chronology of major events leading to the beginning of former President Park Geun-hye's trial on Tuesday.
2016
Oct. 24: Cable TV network JTBC unveils a tablet PC presumed to have been used by the president's longtime friend Choi Soon-sil, and reports allegations of her receiving and editing drafts of presidential speeches.
Oct. 25: Park apologizes over a leak of presidential speeches to Choi.
Oct. 27: State prosecution establishes a special task force to investigate allegations surrounding Park and Choi.
Oct. 29: Liberal civic groups hold first anti-Park candlelight rally. Prosecutors attempt to raid the presidential office Cheong Wa Dae, but are denied entry.
Oct. 30: Park accepts the resignations of her five secretaries implicated in the corruption and influence-peddling scandal. They are Woo Byung-woo, An Chong-bum, Lee Jae-man, Jeong Ho-seong and Ahn Bong-geun. Choi returns home after weeks of apparently hiding in Europe.
Oct. 31: Choi is taken into custody with an urgent arrest without a warrant after hours of questioning by prosecutors.
Nov. 3: Choi is formally arrested.
Nov. 4: Park delivers a second national address, offering to face investigations regarding the scandal.
Nov. 6: Ex-presidential secretaries An and Jeong are formally arrested. Former aide Woo undergoes questioning.
Nov. 8: Prosecutors raid offices of Samsung Electronics Co. on suspicions of offering bribes to Choi, and in effect to the president.
Nov. 14: The National Assembly passes a bill for an independent counsel to investigate the scandal.
Nov. 20: Choi is indicted along with Park's former aides An and Jeong. Prosecutors name Park as a criminal suspect, accusing her of colluding with those indicted.
Nov. 29: Park delivers her third national address, calling on parliament to determine her fate as president.
Nov. 30: Prosecutor-turned-lawyer Park Young-soo is appointed the special counsel to investigate the corruption scandal.
Dec. 6: A special committee of the National Assembly questions a group of business tycoons over their donations to two nonprofit foundations controlled by Choi in the first parliamentary hearing on the corruption scandal.
Dec. 9: The National Assembly passes a motion to impeach Park in an overwhelming 234-56 vote. Park is accused of letting Choi meddle in state affairs and colluding with her to extort millions of dollars from local conglomerates, including Samsung Group. The impeachment resolution is sent to the Constitutional Court for review.
Dec. 11: Justice Kang Il-won is designated as the lead justice for the impeachment trial.
Dec. 15: The court requests the submission of investigation records from state prosecutors and the independent counsel on the corruption scandal that led to Park's impeachment.
Dec. 16: Park submits a written statement at the Constitutional Court's request in which she denied all her charges.
Dec. 21: The independent counsel launches its formal investigation.
Dec. 31: Former head of state pension fund Moon Hyung-pyo is formally arrested on suspicions of instructing the state fund to endorse a controversial merger of Samsung affiliates, which is said to have helped consolidate Samsung Electronics Vice Chairman Lee Jae-yong's control over the business group, and thus his position as the heir to his bedridden father and group Chairman Lee Kun-hee.
Dec. 22: The Constitutional Court holds its first preparatory hearing in the impeachment trial.
2017
Jan. 1: Park meets with the presidential office press corps during which she denies the charges against her.
Jan. 3: The court holds its first formal hearing in the impeachment trial in Park's absence.
Jan. 9: The special parliamentary committee on the influence-peddling scandal holds its final hearing.
Jan. 16: Choi appears at the fifth hearing of the trial after being summoned a second time. She denies any wrongdoing.
Jan. 21: Culture Minister Cho Yoon-sun and ex-presidential chief of staff Kim Ki-choon are arrested over allegations of creating and managing a blacklist of artists critical of the government. Cho resigns from the post.
Jan. 25: Outgoing Constitutional Court Chief Justice Park Han-chul says the court should deliver its ruling by March 13, when another justice is set to retire upon completing her term. Park again rebuts her charges in an interview with a conservative online media outlet.
Jan. 31: Chief Justice Park Han-chul retires after completing his term, reducing the number of justices to eight.
Feb. 2: Special prosecutors attempt to raid the presidential office Cheong Wa Dae, but are again denied entry.
Feb. 7: Ex-Culture Minister Cho Yoon-sun and former presidential chief of staff Kim Ki-choon are indicted over the artist blacklist.
Feb. 16: Acting Chief Justice Lee Jung-mi announces that the final hearing will be held on Feb. 24.
Feb. 17: Samsung's de facto leader Lee Jae-yong is arrested on multiple corruption charges, including bribery and embezzlement.
Feb. 22: The Constitutional Court postpones the final hearing to Feb. 27 after Park's lawyers request it be delayed to early March. Park's lawyers petition for the removal of Justice Kang Il-won, claiming he is biased toward parliament. The court dismisses the request.
Feb. 27: The court holds the final hearing of the trial. Park is absent but makes her final argument in a submitted statement. She pleads innocent. Acting President and Prime Minister Hwang Kyo-ahn refuses to extend the investigation period of the independent counsel.
Feb. 28: Park Young-soo's team wraps up its investigation, indicting 17 more suspects including Samsung's Lee Jae-yong. A total of 30 suspects have now been indicted since the launch of the independent investigation.
March 6: Independent Counsel Park announces the results of his team's investigation into the scandal. President Park is named an accomplice of Choi in taking bribes from Samsung and others in exchange for business favors.
March 8: The Constitutional Court announces it will deliver its ruling at 11 a.m. on March 10.
March 10: The Constitutional Court upholds the parliamentary impeachment of Park with a unanimous decision, immediately removing her from office.
March 21: Park is summoned by state prosecutors for the first time for a face-to-face interrogation that lasts a total of 21 hours, the longest for any former presidents questioned so far in criminal investigations.
March 27: The prosecution files a request with the local court for a warrant for the arrest of Park.
March 30: Former President Park appears at a Seoul district court for a hearing on her arrest.
March 31: A Seoul court issues a warrant for the arrest of Park Geun-hye over corruption charges. The former president is placed in custody at a detention center just south of Seoul.
April 4: Park is questioned at the detention center for the first time.
April 12: Park is questioned at the detention center for the fifth time.
April 17: Prosecutors indict Park on multiple charges, including bribery and abuse of power, and conclude the investigation into the scandal. Lotte Chairman Shin Dong-bin and ex-presidential secretary Woo are also put on trial for alleged bribery and abuse of power, respectively.
May 9: Moon Jae-in, a former human rights lawyer and chief of staff to former liberal President Roh Moo-hyun, wins the election to become South Korea's 19th president.
May 23: The Seoul court begins the criminal trial of Park. The former president makes her first public appearance since her arrest in late March. (Yonhap)