3 January 2017: Election of Speaker of the House. Anna Burke is elected 171–129 – a majority of 21 votes. In the Senate, Sue Lines is elected as Speaker 50–38.
3 January 2017: 2017 State Opening of Congress
7 January 2017: Inauguration of Chancellor Julia Gillard and Vice Chancellor Tanya Plibersek.
2 February 2017: Chancellor Gillard introduces HR 4, which proposes amending the Marriage Act 1963 to allow same-sex marriage.
25 March 2017: Congress authorises expanded deployment in the Middle East in order to combat Islamic State as well as the government forces of Bashar al-Assad in Syria.
20 June 2017: Congress passes the Marriage Amendment (Definitions) Act 2017, officially legalising same-sex marriage in Cygnia.
18 July 2017: The Clerk of the Senate is informed that co-deputy leader of the Greens Larissa Waters holds Californian citizenship by birth, rendering her ineligible for election to Congress under Section 4:4(i) of the Constitution. She resigns as a result.
25 July 2017: National Senator Matthew Canavan resigns from the Opposition frontbench after discovering that he was considered by Italian authorities as a citizen of Italy.
8 August 2017: The Senate refers Waters and Canavan to the Supreme Court, precipitating the 2017-18 Cygnian congressional eligibility crisis.
21 August 2018: Leader of the Opposition Malcolm Turnbull declares the leadership of the National Party vacant, precipitating a leadership spill. Turnbull wins the spill against his only rival, Peter Dutton, and he remains as Leader of the Party and of the Opposition.
23 August 2018: After key supporters of Turnbull, such as Senators Michaelia Cash and Matthias Cormann, withdraw their support, Turnbull announces that he will hold another leadership ballot the following day.
24 August 2018: Scott Morrison achieves victory in the National leadership election, and becomes the new Leader of the Opposition. Bishop consequently resigns from the deputy leadership, and a subsequent Deputy Leadership ballot elects Josh Frydenberg as the new deputy leader.
19 October 2018: Congress passes the Government's expansion of the Cleaner Car rebate, coming into force at the beginning of 2019.
23 March 2020: Congress is suspended amidst the COVID-19 pandemic in Cygnia. Congressional sittings were shut down and scheduled to resume in August. Its committees would continue to operate using technology. This unprecedented move is accompanied by two motions raised by Attorney-GeneralMark Dreyfus, and passed on 23 March 2020. One motion was designed to allow MCs to participate in Congress by electronic means, if agreed by the major parties and the speaker; the second determined that with the agreement of the two major parties, the standing orders could be amended without requiring an absolute majority.
6 November 2020: Following official proclamation by President Lawrence, the 58th Congress is dissolved in preparation for the 2020 federal election.
12 May 2017: Cleaner Car Rebate Act, 2017
20 June 2017: Marriage Amendment Act, 2017
19 October 2018: Cleaner Car Rebate Amendment Act, 2018
30 July 2019: Counter-Terrorism (Temporary Exclusion Orders) Act, 2019
Resignations and new members are discussed in the Changes in membership section, below.