Short answers, pulled from the story.
The Star Chamber was an English court that sat at the royal Palace of Westminster from the late medieval period until 1641. It was composed of privy counsellors and common-law judges and was used to prosecute socially and politically powerful people whom ordinary courts were too intimidated to convict, as well as to hear appeals from common people against the excesses of the nobility.
The Long Parliament abolished the Star Chamber through the Habeas Corpus Act 1640, driven by the severe treatment of John Lilburne and religious dissenters including William Prynne, Alexander Leighton, John Bastwick, and Henry Burton. John Pym led the effort, and the court's use by Charles I as a political weapon during his eleven years of Personal Rule was a cited cause of the English Civil War.
The most widely accepted explanation, first recorded by John Stow in his Survey of London in 1598, is that the room's ceiling was decorated with gilded stars on a blue background. The name is first recorded in writing in 1398 as "Sterred chambre." The jurist William Blackstone proposed a rival theory in 1769 involving a legal term for Jewish contracts, but the Oxford English Dictionary dismissed that etymology.
The Star Chamber's inquisitorial practices, especially its use of the ex officio oath to compel self-incrimination, are considered among the reasons behind the Fifth Amendment's protections against compelled testimony. The "excessive bail" clause of England's Bill of Rights of 1688, itself a reaction to Star Chamber abuses, was reproduced almost verbatim as the Eighth Amendment to the US Constitution.
The ex officio oath required individuals to swear, by virtue of their position alone, to answer truthfully any question put to them in court. It forced defendants into what Edgar Lee Masters called a "cruel trilemma": truthful answers risked self-incrimination, unsatisfactory answers invited perjury charges, and silence brought a contempt finding.
The chamber was demolished in 1806 or possibly as late as 1836, with contemporary records giving conflicting dates. Its materials were salvaged; the door was reused at Westminster School until it was destroyed in the Blitz. The original star-studded ceiling and four tapestries depicting the four seasons were relocated to Leasowe Castle on the Wirral Peninsula in Cheshire.