We may think of Napoleon Bonaparte as the fearsome ruler of Europe who tried to bring down Britain’s greatest generals, but the emperor of France had a softer side too.

The beautiful engagement ring he gave to his beloved wife Josephine is up for auction next week, and it shows that the leader was a lover as well as a fighter.

The simple piece of jewellery comprises two tear-shaped gems, one diamond and one sapphire, set onto a gold band.

It is going under the hammer at the Osenat auction house in Fontainebleau, near Paris, and is expected to fetch up to €15,000 (£13,000).

At the time Napoleon married Josephine in 1796, he was a 26-year-old revolutionary soldier and she was a widow who was six years older than her husband.

Her first husband, Alexandre de Beauharnais, was an aristocrat who supported the French Revolution but later became a victim of guillotine.

When she was re-married she already had two children - one of several factors which meant the groom’s family was deeply scandalised at the match.

The couple wed on March 9, 1796 after being engaged for just two weeks.

Napoleon left France two days later to lead the French army on a successful invasion of Italy, which sealed his reputation as one of the dominant figures in the post-revolutionary state.

He took charge of the government in a coup in 1799, and five years later was declared ‘Emperor of the French’.

The ruler was crowned at Notre Dame cathedral - and after placing the crown on his own head, he turned to Josephine and crowned her as empress.

However, it soon became clear that the ageing wife would never bear her powerful husband a child.

In 1810, they agreed to divorce - but during the ceremony, they read out statements expressing their devotion to one another.

Napoleon married Marie-Louise of Austria two months later in the hope of producing an heir, and was heard to comment: ‘I have married a womb.’

But he apparently never forgot the love he bore to Josephine, and he mentioned her in his last words on his death bed while in exile on St Helena.

He is believed to have cried out: ‘France. The army. The head of the army. Josephine.’

The ring that symbolised their love is remarkably simple given its origins.

‘At the time, Napoleon had very little money,’ said Osenat’s Jean-Christophe Chataignier. ‘The ring is a very ordinary one.’

The official estimate for the ring is €10,000 to €15,000.

It is included in a major auction of historical items taking place next Sunday.

One of the many other unique treasures included in the sale is a ceremonial silver sword given to an aristocrat by King Henri IV in 1592.