When the Sultanate of Malacca fell to the Portuguese in 1511, Sultan Mahmud Shah 1 fled to Kampar, Sumatra and died there in 1528. He was given a Royal burial and thereafter given the title Marhum Kampar. The Sultan’s reigning descendants in Perak continue using the posthumous title of Marhum to this day.
Marhum is defined by Yule* as one who has found mercy (the root arabic word being rahim رحيم – mercy. –Eds.). It is customary to discontinue, after the death of a Sultan, the use of the title which he bore during his lifetime. A new title is created, usually by the state ulama’, for the deceased monarch by which he is ever posthumously known. For instance, the 28th Sultan of Perak, Almarhum Paduka Seri Sultan Idris Murshidul Azzam Shah I was given the title Marhum Rahmatullah.
The existence of a similar custom among other Indo-Chinese races have been observed by Yule.
There is also a custom of dropping or concealing the proper name of the King after death which exists in Burma and, according to La Loubere, in Siam. The various kings of those countries are generally distinguished by by names derived from personal attributes or events during their reign, and are applied to them after death. Colonel Yule further ascribed the origin of this custom to Ancient India.
Source: Maxwell, W. The history of Perak from native sources. Journal of the Straits Branch Royal Asiatic Society. 1881 June. p97-99.
[*] Colonel Sir Henry Yule, retired in 1862 at the rank of Colonel, had devoted his leisure to the medieval history and geography of Central Asia. He published Cathay and the Way Thither (1866), the Book of Marco Polo, for which he received the gold medal of the Royal Geographical Society. He also brought out, in collaboration with Dr Arthur C. Burnell and Hobson-Jobson (1886), a dictionary of Anglo-Indian colloquial phrases. He died December 30 1889.