Marius Pontmercy (French pronunciation: [maʁjys pɔ̃mɛʁsi]) is a fictional character, one of the protagonists of Victor Hugo’s 1862 novel Les Misérables.

All his life, he has been told that his father (Georges Pontmercy, a colonel under Napoleon) abandoned him to Gillenormand.

Marius begins looking up his father in the official military histories and after learning that his father was a highly decorated veteran of Napoleon's army, who had been made a baron and a colonel by Napoleon (though neither the barony nor the rank of colonel is recognized by the current regime).

Marius meets Courfeyrac, a fellow student, who introduces him to a society called the Friends of the ABC, a political group committed to republican revolution.

Almost immediately, Marius' Bonapartist beliefs come into conflict with the republican views of the group's members.

"[1] Marius descends further into poverty and, despite all his hardships, manages to complete his studies and become a recognized lawyer.

On Courfeyrac's advice, he learns German and English in order to work for a publisher translating manuscripts into French.

Marius regularly takes walks in the Luxembourg Garden, where he frequently sees Cosette and Jean Valjean, and does not pay much attention to either.

After a six month break from walking in the Luxembourg Gardens, he returns to find that Cosette has quickly grown into a young lady, and falls in love with her.

Valjean learns of this and, fearing that Marius is a spy working for the police inspector Javert, moves away that week.

Back at his apartment, he examines the four letters it contains and realizes that they are fraudulent pleas for help, all in the same handwriting with the same misspellings, but containing different stories and signatures.

Peering through a crack in the wall, Marius sees Jean Valjean and Cosette talking with Jondrette about returning to give the family money.

Distressed, Marius visits Javert, who gives him two pistols and instructs him to fire them during the robbery.

Marius, after some days of waiting, decides to write a 15-page love letter to Cosette which she finds hidden under a stone.

Marius drives them away by holding a torch to a powder keg, and threatens to blow up the barricade.

Marius writes a letter back to Cosette, saying since she left again with no forwarding address, he would fulfill his promise and die for her.

While Marius quietly searches for the real origin of Cosette's money, Valjean loses the will to live.

A few weeks later, a disguised Thénardier comes to Marius's residence to visit the Baron Gillenormand, attempting to blackmail Valjean.

He then gives Thénardier a large sum of money, repaying his father's death, and orders him to leave France for America.

Since the original publication of Les Misérables in 1862, the character of Marius has appeared in a large number of adaptations of the novel, including books, films,[2] musicals, plays and games.