In 1658, the Sultan of Brunei gave Sabah to Sultan of Sulu and Palawan for his help in sending Tausug warriors to stop a rebellion and civil war. Since then, Sabah became a property of the Sultan of Sulu and the Sultanate of Sulu.
In 1878, HM Sultan Jamalul Ahlam Kiram (the Sultan of Sulu and the Sultan of Sabah), leased Sabah to a British compary of Gustavus Baron de Overbeck and Alfred Dent “The North Borneo Company,” for their use and their heirs.
The lease prohibits the transfer of Sabah to any nation, company or individual without the consent of the government of the Sultan of Sulu.
In 1946 or 1947, the lease was illegally transferred to the British government by Overdeck and Dent when their company North Borneo ceased to exist.
Ceded to the Philippines
On September 12, 1962, the still on lease territory of North Borneo (SABAH), and the full sovereignty, title and dominion over the territory were ceded by the then reigning Sultan of Sulu HM Sultan Muhammad Esmail E. Kiram I, to the Republic of the Philippines.
The cession effectively gave the Philippine government the full authority to pursue their claim in international courts.
In 1963, the British illegally transferred Sabah to newly formed Federation of Malaysia. The territory they illegally obtained from Overdeck and Dent’s North Borneo Company was again transferred illegally to Malaysia.
Upon the illegal inclusion of Sabah into Malaysian Federation, President Diosdado Macapagal broke diplomatic relations with Malaysia.
Marcos and Operation Merdeka
In 1967, President Ferdinand Marcos initiated Operation Merdeka involving the training of Commandos in Corregidor. Their task was to infiltrate Sabah.
Ninoy Aquino, a filibuster in the Philippine Senate, exposed the secret operation. Because of the expose, “Operation Merdeka” became a big failure. It caused the deaths of Filipino military and civilian operatives inside Sabah.
What happened next was known as Jabidah Massacre, named after the Jabidah Commandos.
Since then, no other president of the Philippines has ever tried to recover Sabah either by peaceful means through the International Court of Justice (ICJ) or military means, making Marcos the only one to ever attempt to do so.
27 years after Marcos, Sabah is still in the hands of Malaysia.
Text taken from http://www.youtube.com/watch?v=v9jfRcXeQc4