 The younger son Wan Ahmad challenged the succession of his half-brother Tun Mutahir, in a dispute that escalated into a civil war.Supported by the neighbouring Terengganu Sultanate and the Siamese, Wan Ahmad emerged victorious, establishing controls over important towns and expelled his brother in 1863.He served as the last Raja Bendahara, and was proclaimed Sultan of Pahang by his chiefs in 1881.