Jamalul Kiram III, a Philippine sultan whose armed followers invaded a vast Malaysian region and sparked a security crisis in February that left dozens dead, died Oct. 20 at a Philippine hospital. He was 75.

The cause was multiple organ failure, said his wife, Fatima Celia. She adding that before he died he ordered his family and followers to keep alive the historic territorial claims to Sabah state in neighboring Malaysia.

Although largely forgotten and dismissed as a vestige from a bygone era, Mr. Kiram’s Muslim sultanate, based in the southern Philippine province of Sulu, stirred up a security crisis in Malaysia when his younger brother and about 200 followers, dozens of them armed, barged into Sabah’s coastal village of Lahad Datu.

Stunned, Malaysia responded by sending in ground troops and launching airstrikes. Dozens were killed in weeks of sporadic fighting before the standoff eased.

Malaysia has governed the resource-rich frontier region of timberlands and palm oil plantations in northern Borneo as its second-largest federal state since the 1960s.

The Kiram sultanate, which emerged in the 1400s, built a legend for its wide influence at the time and its feared Tausug warriors. Chinese and European leaders once sent vassals to pay homage to their powerful forebears, sultanate spokesman Abraham Idjirani said. The Sulu sultanate preceded both the Philippine republic and Malaysia by centuries.

But overrun by history, the Kirams now carry royal titles and nothing much else.

“I’m the poorest sultan in the world,” an ailing Mr. Kiram said in an interview in March at his run-down residence in a Muslim village in the Philippine capital.

The Kirams claim Sabah has belonged to their sultanate for centuries and was only leased to Malaysia, which they say pays them a paltry annual rent. Malaysian officials contend that the payments are part of an arrangement under which the sultanate has ceded the 28,000 square miles of Sabah territory to their country.

Philippine presidents have relegated the volatile feud to the back burner despite efforts by the Kirams to put it on the national agenda.

Mr. Kiram’s sultanate still has hundreds of followers in Sulu and nearby southern provinces, which are among the Philippines’ poorest and are troubled by Muslim rebels, al-Qaeda-linked extremists and outlaws.

Mr. Kiram’s family said he would be buried in his hometown of Maimbung in Sulu.

He is survived by eight children and is likely to be replaced by a younger brother, Esmail Kiram II, in a succession often marred in the past by clan infighting and claims by fake descendants of the once-powerful Muslim royalty.

— Associated Press