Moshe Arens, who died this week, was the young Benjamin Netanyahu's mentor

Born in Lithuania but raised in the United States, he was a qualified engineer who first moved to Israel after independence.

In 1974 he was elected to the Knesset for Likud. He believed in holding Israel’s generals to account, and this appealed to Prime Minister Begin, who offered him the Defence Ministry in 1980.

However, Mr Arens declined, as being minister meant he would have to implement Israel’s pullback from Sinai, a step he had opposed in the belief that Egypt, which had fought four wars against Israel and lost, did not deserve to receive the entire peninsula back.

But Mr Begin would soon offer him another top job: Israel’s ambassador in Washington.

On the eve of his departure, he tapped the thirty-one year-old Benjamin Netanyahu as his deputy.

Mr Netanyahu was then a sales manager in a furniture company, but Mr Arens was a friend of his family and had been impressed by him in a conference he had organised in 1979, and believed he could be a persuasive spokesperson for Israeli policies in the American media.

For the next decade, Mr Arens was to be the young Netanyahu’s mentor.

In 1992, following Likud’s election defeat, Yitzhak Shamir resigned as party leader and Mr Arens was widely expected to succeed him.

Mr Netanyahu was already preparing to serve as his campaign manager.

But he surprised his supporters by announcing that he believed in “service, not servitude” and announced he would leave politics.

It was Mr Netanyahu who ran instead — and won.

Mr Arens made one brief comeback when, in 1999, he ran a brief leadership challenge.

It was a symbolic campaign, a protest against his protege’s signing of the Wye Accords transferring control of part of the West Bank to the Palestinian Authority.

Mentor lost to pupil and immediately agreed to serve as his defence minister, a third stint in that office.

While he often expressed pride in Mr Netanyahu’s career, — “I discovered him”, he said — he publicly differed with him on key issues, such as making Avigdor Lieberman defence minister and the Nation State Law.

In Israel’s rowdy politics, he was recognised on all sides as a rare gentleman, devoid of burning ambition, who saw politics as public service, not a career.

In retirement he spent much of his time researching and writing the story of the little-known Beitar resistance group in the Warsaw Ghetto, Jewish Military Union. Deep political differences however did not prevent Mr Arens from befriending the last survivors of the Warsaw Ghetto Uprising in the process.

Last month, he wrote a Haaretz eulogy for Simcha (Kazik) Rotem, the last living fighter from the ghetto.

It to be his own last column as well.