Sultan Qaboos of Oman returned home on Monday after spending more than eight months in Germany for medical treatment that was completely successful, state television reported.
Qaboos returned after "having completed medical treatment in Germany whose results were crowned as a total success," the television announced as it showed the 74-year-old who was thin but walking with ease from a royal plane and along a red carpet.
In his last public address, Qaboos appeared on television in November to tell his nation that he would miss the 44th anniversary of his inauguration and national day, saying his treatment was giving "good results".
A diplomatic source in Muscat had said the sultan, who has ruled Oman since overthrowing his father in a bloodless 1970 coup, was suffering from colon cancer.
When he took the reins of power, Oman was an isolated country living on the margins of the modern world with little or no infrastructure.
Qaboos has since transformed his Gulf sultanate -- which sits atop proven gas reserves of 660 million cubic metres (23.3 billion cubic feet) -- into a modern state.
In October 2011, Qaboos, who has no children or brothers, amended the process of choosing his successor.
The sultan, whose closest relatives are cousins, appointed five top officials to a council that would be involved in confirming the new sultan in case of any royal family dispute.