Malaysia Prime Minister Mahathir Mohamad has reached another milestone at age 94.

On Aug. 5, 2019, he celebrated his 63rd wedding anniversary with his wife, Siti Hasmah Mohd Ali.

Tribute

Marina Mahathir, the eldest daughter of Mahathir and Siti, paid tribute to her parents who are both doctors.

Siti is only one year younger than Mahathir.

Malaysia's best couple

Hailed as the sweetest couple in Malaysia, Mahathir and Siti met at Singapore's King Edward VII College of Medicine -- now part of the National University of Singapore -- in 1947.

They tied the knot in 1956.

Secret to marriage?

The secret to their six-decade coupling?

Tolerance and acceptance.

Mahathir once said of his love: "At first of course, when we were young, we had differences, tension and all that."

"But as you grow older you realise that you cannot change your partner very much and she cannot change me very much and we learn to accept that this is what the person is like."

He also said their quarrels are over minor things that can be resolved easily.

"My wife always says that behind every successful man, there is a wife, not just a woman," Mahathir also said.

Marina previously paid tribute to her parents in an article in 2016, revealing that showing physical affection in the family was the norm.

Seven children

The couple have seven children.

They have four biological children: One girl and three boys — Marina, Mirzan, Mokhzani and Mukhriz.

They also adopted three children -- Melinda, Mazhar and Maizura.

Mahathir's first tenure as prime minister was from 1981 to 2003, becoming Malaysia's longest-serving prime minister.

He made a comeback in the 14th general election in May 2018.