He is best remembered for his defiance of the king on 4 January 1642 when Charles entered the chamber of the House of Commons, supported by 400 armed men, in an attempt to seize five members whom he accused of treason.

Lenthall's mother, Frances (sister of the Jesuit priest and poet Robert Southwell),[3] conformed to the established Church.

[3] He failed to be re-elected in 1625,[4] but again represented the constituency during the 1640 Short Parliament, on several occasions being called upon to chair grand committees of the House on important subjects, including ship money and parliamentary grievances.

[5] However, the journal of Sir Simonds d'Ewes (who was not generally supportive) suggests that in the opening months of the Long Parliament Lenthall was very much in control of proceedings.

[5] By late 1641 Lenthall was finding the House's long sittings physically exhausting and he became increasingly desperate to be relieved of the speakership.

[7] Charles's intended show of strength having failed, he left London less than a week later,[6] and within months the country was plunged into civil war.

[5] In the last speech that Lenthall delivered to the king he talked of reconciliation, and invited Charles to rid himself of false counsellors.

Lenthall remained in the chair, supporting the Parliamentary cause but without much sympathy toward those diehard Protestants who were seeking radical ecclesiastical reform.

[8] Lenthall's appointment to a series of high offices during this period brought some relief to his preoccupation with his personal finances.

He had already called attention to the inadequacy of his salary and been granted a sum of £6,000,[9] and during the 1640s he became Master of the Rolls, a commissioner of the Great Seal, and Chancellor of the Duchy of Lancaster.

[8] The Long Parliament found itself increasingly unpopular, having imposed punitive taxation and chosen a course which had led to slaughter without any identifiable achievement.

[10] On 26 July a mob invaded parliament to force it to agree to the army's Solemn Engagement[11] (its refusal to disband until its grievances were met).

[12] The fugitive members were well received by the soldiers, and they were invited by their commander Lord Fairfax to review 15,000 men on Hounslow Heath on 3 August.

[12] Fairfax's regiments encircled London the next day, and under his protection Lenthall and the other fugitives were escorted in triumph back to parliament.

[12] Lenthall sympathized with the Independents in parliament, and was portrayed by royalist newspapers in 1648 as being their tool, plotting to manipulate the House in their interests.

[7] Lenthall remained in post during the debates and resolutions that led ultimately to Charles's execution on 30 January 1649, though there is no evidence that he was otherwise active in the events leading up to the regicide.

[15] Lenthall, along with the other lawyers present, argued against the idea of a pure republic and in favour of a mixed constitution incorporating some role for a monarch.

[19] In the Second Protectorate Parliament, summoned by Cromwell on 17 September 1656,[20] Lenthall was again returned as member for Oxfordshire,[19] but this time was not selected as speaker.

The Protectorate rapidly collapsed, and on 6 May 1659 Lenthall was visited by senior army officers who asked him to help with the revival of the Rump Parliament, and to return as speaker.

[21] Lenthall was reluctant to give up his seat in the Other House[22] and pleaded ill health, but when he was bypassed and parliament summoned without his aid he felt himself obliged to resume his role as speaker the following day.

[21] On 12 October 1659 the army surrounded and occupied the precincts of the House, and for a night and a day a stand-off with the parliamentary defenders ensued.

[25] Lenthall began to manoeuvre away from the republicans, and in November was reported to have been in touch with General George Monck[21] who was actively working against factions within the army that opposed the Rump.

The situation had completely changed by 24 December when Lenthall was approached at home and his permission sought, as head of the army, for troops to parade in Lincoln's Inn Fields.

[26] Soldiers who had earlier refused to recognise Lenthall's authority now marched to his house to acclaim him with shouts and a volley of shots.

[21] Lenthall was at risk of being put on trial by the new regime for some of his acts during the interregnum, and he was strongly denounced by William Prynne.