Josephine Ruby Trevorrow

Enche’ Besar Hajah Khalsom binti Abdullah (born Josephine Ruby Trevorrow; 2 December 1935 – 1 June 2018) was the first wife of Sultan Iskandar and mother of Sultan Ibrahim, who is the current Sultan of Johor and then the seventeenth Yang di-Pertuan Agong (King of Malaysia) since 31 January 2024. One of her daughters Tunku Azizah married Sultan Abdullah, the current Sultan of Pahang who also became the sixteenth Yang di-Pertuan Agong.

She was born on 2 December 1935 in Cornwall in England, the daughter of Reginald George Trevorrow and Ruby May Alderman. She met Iskandar while he was studying in England. After that she converted to Islam and changed her name to Khalsom binti Abdullah, they married on 5 January 1956. On 8 May 1959, after her husband proclaimed the title of Tunku Mahkota (Crown Prince) of Johor, she was then known as Yang Amat Mulia Che’ Puan Khalsom Abdullah. This royal couple had four children:

• Tunku Puteri Kamariah Aminah Maimunah Iskandariah (b. 11 July 1956), the Tengku Puan Laksamana of Selangor
• Tunku Besar Zabedah Aminah Maimunah Iskandariah (b. 20 October 1957)
• Sultan Ibrahim ibni Almarhum Sultan Iskandar (b. 22 November 1958), the seventeenth Yang di-Pertuan Agong (King of Malaysia) and the fifth Sultan of modern Johor.
• Tunku Hajah Azizah Aminah Maimunah Iskandariah (b. 5 August 1960), the fifth Tengku Ampuan of Pahang and the sixteenth Raja Permaisuri Agong (Queen consort of Malaysia)

On 9 June 1962 they divorced, shortly after Iskandar's second marriage to Tengku Zanariah, and she returned to England.

Later in 2010, her son Ibrahim, who had just become the Sultan of Johor, bestowed upon her the honorific form of address as Yang Amat Mulia Enche’ Besar Hajah Khalsom Abdullah, D.K., S.M.I.J. She died aged 82 on 1 June 2018 at King Edward VII's Hospital in London and was buried on 6 June in the Mahmoodiah Royal Mausoleum in Johor Bahru.