Thousands of Samoans turned out to bid farewell to their head of state, Malietoa Tanumafili II, who died last week at the age of 94.
Malietoa Tanumafili II ruled the South Pacific nation for 45 years
Chiefs in traditional mourning attire stood alongside foreign dignitaries for the ceremony in the capital, Apia.
Prime Minister Tuilaepa Sailele Malielegaoi praised Malietoa's "long and valuable services" to the nation.
Dubbed "the father of Samoa", Malietoa had ruled the nation since it gained independence from New Zealand in 1962.
He was the world's third-longest serving head of state, after King Bhumibol Adulyadej of Thailand and Queen Elizabeth II.
Malietoa's body lay in state overnight inside parliament before being placed outside on a decorated platform for the funeral ceremony.
Traditional rulers from around the South Pacific region gathered to pay their respects, alongside New Zealand Prime Minister Helen Clark and Australian Governor-General Michael Jeffrey.
"Samoa's deep grief is shared... by all these people," the prime minister said, describing Malietoa as "the personification of Samoan peace and unity".
Bare-chested warriors in woven mourning mats and orange flower garlands surrounded the platform as the funeral took place. The late leader was then interred in his family crypt, with a cannon salute.
Malietoa, who was appointed for life, was the world's oldest head of state when he died.
He was the architect of Samoa's constitution, under which the country's next head of state will be selected by the legislature for a five-year term.