Mahathir Mohamad submitted his resignation from the post of Malaysia's prime minister to the king on Monday in a shocking turn of events.
The announcement was made amid plans by Mahathir's supporters to join with opposition parties to form a new government that would exclude Anwar Ibrahim, his anointed successor, reports Al Jazeera
Ibrahim, Malaysia's prime minister-in-waiting for a second time, has accused the party of Prime Minister Mahathir Mohamad and "traitors" in his own camp of planning to bring down the ruling coalition and form a new one to deny him the premiership, reiterating their decades-old clash.
Here are the key details of the feud between Ibrahim and Mahathir that has dominated Malaysian politics for years:
1982: As a rising young politician, Anwar joins Mahathir's party, the United Malays National Organisation (UMNO), soon after the latter became prime minister for the first time.
1993: Anwar rises rapidly in the party to become deputy prime minister, on course to succeed Mahathir.
1998: Months of feuding with Mahathir over Malaysia's handling of the Asian financial crisis culminates in Anwar's sacking. In opposition, Anwar wins support from a large section of Malay Muslims, the dominant ethnic group in the multicultural country, to drive his Reformasi movement.
1999: Anwar builds on the Reformasi momentum and founds the Parti Keadilan Nasional or National Justice Party (KEADILAN) a forerunner of the later Parti Keadilan Rakyat (PKR), or the People's Justice Party. Separately, Anwar is convicted and jailed for corruption and sodomy, charges he maintains were politically motivated.
2003: Mahathir steps down after 22 years as prime minister.
2004 to 2013: Four years after his 2004 release, Anwar is again accused of sodomy by a male aide. Anwar says the accusations aimed at removing him from his post as leader of the opposition, which came close to defeating Najib Razak - another Mahathir protege - in the disputed 2013 election.
2015: During Najib's administration, Anwar is jailed for sodomy for the second time.
2016 to 2017: Mahathir quits UMNO amid calls for Najib to resign over a multibillion-dollar corruption scandal at the 1MDB state fund. Mahathir forms a new party, Bersatu, before joining forces with Anwar's opposition coalition, Pakatan Harapan (PH). He promises to seek a royal pardon for Anwar and hand him the premiership if the coalition succeeds in its bid to remove Najib and the UMNO-led government.
2018: The pair joined forces to win the election and remove UMNO from power. Mahathir leads the opposition coalition to an unprecedented victory in a May 9 general election, ending UMNO's 60-year rule. Within a week, Anwar is pardoned and released.
2019: Anwar denies accusations of having sexually assaulted a former male aide, describing them as "politics at its worst". The case was dropped on grounds of insufficient evidence.
2020: Mahathir faces pressure from Anwar's allies in the coalition to set a date for the handover of power, sources say. Separate meetings at the weekend between politicians from the ruling coalition and UMNO spark talks of a possible alliance to form a new government. Anwar blames the bid on "our former friends" in Mahathir's Bersatu and "a small faction of traitors" from his own party.