Incoming President of the Philippines, Rodrigo Duterte recently vowed to pursue his country’s claim over Sabah.

Malaysia’s government was quick to issue a response.

It’s not the first time Sabah’s sovereignty has made the headlines, and this latest episode sparked mixed reactions among Malaysians.

Is such a claim over Sabah, valid under international law?

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The Malaysian state of Sabah, formerly known as North Borneo, was once a territory of the Sultanate of Brunei.

In 1658, the Sultan of Brunei ceded the northern and eastern portion of Borneo to the Sultan of Sulu in compensation for the Sulu’s assistance in repressing civil war that erupted in Brunei at that time.

At its peak in the 18th century, the influence of the Sultanate of Sulu extended beyond the territory of the modern day Sabah to include the southern Philippines as well.


The advent of the colonial powers of Britain and Spain saw the gradual depletion of the influence of the Sulu Sultanate.

While the rest of the Philippines fell under Spanish dominions, British took the initiative to gain power in Sabah.

The Americans dissolved the political sovereignty of the Sulu Sultanate through the Carpenter Agreement signed on 22 March 1915.

Sabah and the Sultanate of Sulu

On 22 January 1878, an agreement was signed between the Sultanate of Sulu and two British agents, Alfred Dent and Baron von Overback (German by nationality) which provided that North Borneo was ceded or ‘leased in perpetuity’ to the British, in return for payment of 5, 000 Malayan dollars per year.

The lease was increased to 5, 300 Malayan dollars a year when the territory ceded was extended to include additional islands along the coast of North Borneo from Banggi Island to Sibuku Bay.
Upon cession, the British North Borneo Chartered Company (BNBC) administered Sabah until 1941.

Sabah was then annexed as part of the Japanese Empire. Upon Japanese surrender in 1945, Sabah was made a British crown colony until its independence within Malaysia in 1963.

The Philippines began it’s claim over Sabah in 1963 but agreed in 1977 not to pursue it.

Sabah, Malaysia

However, the current President-elect was reported to have decided not to drop the claim, based on the fact that Sabah had traditional and ancestral ties with the dissolved Sulu Sultanate.

It is not entirely clear whether or not the Philippines would pursue this through the International Court of Justice (ICJ).

Territorial Acquisition and Recognition under International Law

There are a number of methods of territorial acquisition under international law, among others, through conquest, prescription and cession.

Conquest or annexation was recognised as a method of territorial acquisition in the past but has been deemed illegal under international law at least when the United Nations (UN) Charter came into force in 1945.

Therefore, the most relevant for Sabah is cession and prescription.

A State may acquire sovereignty over a certain territory if the sovereignty is transferred or ceded by the sovereign to another.

Sabah was ceded to the British by the Sultanate of Sulu in 1878, and was later transferred to Malaysia in 1963.

Under international law, prescription refers to acquisition of sovereignty by way of actual exercise of sovereignty and such is maintained for a reasonable period of time.

Malaysia has, since 1963, administered Sabah without any persistent objection from any members of the UN.

Malaysia’s exercise of sovereignty over Sabah is different with that of Indonesia in relation to East Timor.

East Timor was annexed by Indonesia in 1975. Due to protests from the international community and the East Timorese themselves, East Timor became an independent sovereign State in 2002.

Sabah was never annexed as it, through the Cobbold Commission, voluntarily decided to be federated into Malaysia together with the British colonies of Singapore and Sarawak as well as with the independent sovereign of Malaya.

Since 1963, Malaysia has installed a working government to administer Sabah, invested funds to develop its economy with the international community recognising Sabah as part of Malaysia.

Historical / Ancestral Claims

The claim of Sabah as ancestral territory of the Sultan of Sulu is baseless.

The ICJ in the 2008 Malaysia-Singapore dispute over Pedra Branca recognised that Pedra Branca was not terra nullius (no-man’s land) and the sovereignty over it was with the Johor Sultanate.

The ICJ however awarded Pedra Branca to Singapore when it was proven that the British government of Singapore has acquired it from the Sultan of Johor since 1953.

If ancestral claims hold strong position under international law, then Pedra Branca should remain with the Johor Sultanate (Malaysia) and not with Singapore.

In addition, if historical claims could be upheld, then, Malaysia, through the existing Johor Sultanate could put a claim on Singapore and the Riau Islands of Indonesia.


Malaysia too, via the historical territories of the Kedah Sultanate, could claim sovereignty over Thai provinces of Satun and Trang as well as Tenasserim in Myanmar.

This is nevertheless, not how international law operates and shows that ancestral claims do not carry much weight under international law.


Historically, Sabah was part of the Sulu Sultanate.

Nevertheless, the political scenario of Sabah and the Philippines have changed since the Spanish, the British and the Americans came to this part of the world with the aim of colonisation.

Sabah is now part of Malaysia and has been progressing well towards development and modernisation.

The relative prosperity of Sabah has turned it into a gold-mine not only for Malaysians, but also for non-Malaysians residing in the state.

Regardless of such unwanted claims, the international community has, without doubt, acknowledged Sabah an integral part of Malaysia and therefore shall remain as such.

Mohd Hazmi Mohd Rusli is a senior lecturer at the Faculty of Syariah and Law, Universiti Sains Islam Malaysia and a visiting professor at the School of Law, Far Eastern Federal University, Vladivostok, Russia.

Views expressed are personally those of the author and do not necessarily reflect those of Astro AWANI.