SINGAPORE - He was Singapore's former president, but Mr Ong Teng Cheong was once also known as a "musketeer".

To be exact, Mr Ong and four classmates at the then-Chinese High School (CHS) in the 1950s were referred to as the "Five Musketeers" for standing up to left-wing students and refusing to support their Communist cause.

While the quintet would openly defy left-wing students in not taking part in the boycotts or strikes, they would, however, occasionally join in for "good" causes like helping the victims of floods and fires.

"However, we never supported their Communist cause even though we were also anti-British, anti-colonialism, and pro-independence.

"Also - and perhaps more importantly - because we often helped them with their homework, the left-wingers left us alone, and labelled us 'The Five Musketeers'," wrote Mr Ong in private memoirs about his childhood.

These details were revealed for the first time in a book to mark the 100th anniversary of Hwa Chong Institution, the product of the merger of CHS and Hwa Chong Junior College in 2005.

Mr Ong Tze Guan, 53, the elder of the former president's two sons, had contributed excerpts from memoirs written by Mr Ong, which were left behind after his death.

Mr Ong served as Singapore's first elected president from 1993 to 1999 and died at 66 years old in 2002.

The younger Mr Ong, who is now the chief executive of Singapore-based company Glowtec Bio, wrote in the submission: "My father's years in CHS were formative ones that had a profound influence on his development.

"The rich and diverse experiences he had in the school helped to shape his worldview and mould him as a person of great character."

Giving details at a press briefing on Sunday, the editorial committee behind the book said the 644-page book containing over 540,000 words is the school's most comprehensive effort to date.

It documents the school's history from before World War 2 to today through the eyes of alumni, former teachers and principals, and members of the school's board of directors.

Other notable names among the contributors include Singapore Management University School of Law's Dean Goh Yihan, and the National University of Singapore's provost and senior deputy president Professor Ho Teck Hua.

The book's 170 submissions by some 200 authors took two years to compile and edit, said Mr Robson Lee, chairman of the school's board of directors.

Besides photographs and personal stories, the book features profiles of notable alumni; accounts of the school's co-curricular activities such as the Chinese drama club; poetry and prose pieces; and the authors' aspirations for Hwa Chong's future.

The submissions are mostly in Chinese, but a handful, like Mr Ong's, are in English.

Mr Lee said: "Hwa Chong has a rich heritage and history. We hope that this compendium of our efforts and struggles can serve as a reference for Hwa Chong members in the future."

The book will be available on March 21, the school's Founder's Day, when a celebratory gala dinner will also be held for over 12,000 alumni and other members of the Hwa Chong family.

Members of the public can contact the Hwa Chong Alumni Association after the book's launch to purchase a physical copy, which will cost $60. Proceeds from the sales will be donated to the school fund.

The 2.5kg book comes bundled with a collection of the school's badges of various designs through the years. About 1,000 out of 4,500 copies in the initial print run have already been bought by alumni.

Mr Lee said some copies of the book will also be donated to libraries here, and more copies will be printed if there is interest.

The editorial team also plans to launch a free e-book version on the alumni association's website by the end of the year, Mr Lee added.