A new four-person panel has been named by Home Secretary Theresa May, as the inquiry into child sex abuse in England and Wales officially starts work.
The panel members are Professor Alexis Jay, Drusilla Sharpling, Ivor Frank and Professor Malcolm Evans.
They will serve alongside the New Zealand judge, Lowell Goddard, who is heading the inquiry.
New terms of reference have been agreed, which include removing any cut-off dates.
Mrs May said the inquiry would also reflect the importance of survivors, who will be able to appear as witnesses.
The inquiry will have statutory powers to compel witnesses to determine whether institutions took seriously their duty of care to protect children from sexual abuse in England and Wales.
The home secretary issued a written statement confirming she had set up the statutory independent inquiry into child sexual abuse with Justice Goddard as chairman.
Established under the Inquiries Act 2005 it has considerably more powers than its predecessor.
Justice Goddard appeared before the Home Affairs Select Committee in a pre-appointment hearing last month and it endorsed her appointment.
Mrs May said Justice Goddard was "as removed as possible from the organisations and institutions that might become the focus of the inquiry".
Since the original child abuse inquiry was set up in July 2014, two chairwomen have resigned amid concerns over their links with the establishment.
Baroness Butler-Sloss, Mrs May's first choice as inquiry chairwoman, resigned a week after it was set up. She faced calls to quit because her late brother, Sir Michael Havers, was attorney general in the Thatcher cabinet.
Her replacement, City lawyer Fiona Woolf, stood down in October amid concerns over her links to former Home Secretary Lord Brittan.
The original inquiry was sparked by claims of paedophiles operating in Westminster in the 1980s.
The inquiry will investigate whether "public bodies and other non-state institutions have taken seriously their duty of care to protect children from sexual abuse in England and Wales".
Justice Goddard said she was "honoured" to lead the inquiry: "The many, many survivors of child sexual abuse, committed over decades, deserve a robust and thorough investigation of the appalling crimes perpetrated upon them."
On the new appointments announced on Wednesday, Mrs May said: "I have decided to appoint four panel members, who have the range of skills and expertise required to take forward and lead the important work of the Panel in supporting the chairman."
Prof Jay has expertise in social work and led the inquiry into child sexual exploitation in Rotherham.
Ms Sharpling is a qualified barrister with expertise in both policing and the Crown Prosecution Service.
Mr Frank has extensive experience in family and human rights law, and expertise in child protection matters.
Prof Evans is chairman of the United Nations subcommittee for the prevention of torture and professor of public international law at the University of Bristol. Educated in Cardiff, he has a Welsh perspective, which survivors have called for.
The home secretary said: "In addition, the panel will be informed by a number of expert advisers in the fields of health, education, and a psychologist with expertise in this sensitive area.