To Americans of the 1920s and ‘30s, he was the notorious gangster Scarface Al, Public Enemy No. 1. But when he arrived at Alcatraz in late August of 1934, Alphonse “Al” Capone took on a more humbling name: Prisoner 85.

As Prisoner 85, Al Capone led a very different life from his freewheeling days at the top of the Chicago rackets. He became a serious reader, a musician and a composer. A model prisoner, he kept a low profile, did his prison chores and rarely resorted to violence unless he was provoked—in one instance bashing a fellow inmate’s head with a bedpan.

It would be a stretch to say that Al Capone was the Renaissance man of Alcatraz, but he appears to have lived up to his promise to mend his evil ways—at least temporarily.

Alcatraz, located on a rocky island in San Francisco Bay and nicknamed The Rock, opened for business in August 1934, shortly before Capone arrived. It was a federal maximum-security prison, considered all but escape-proof. Capone, who had been serving his sentence in Atlanta, was transferred there along with more than 100 other prisoners from across the U.S.

Technically a white-collar criminal, convicted of tax evasion in 1931, Capone was an unusual choice for the prison’s freshman class. Jonathan Eig, author of Get Capone: The Secret Plot That Captured America’s Most Wanted Gangster, tells HISTORY he thinks assigning Capone there was basically a government PR ploy to “show off their new prison and justify its cost. What better than sending the most notorious gangster in the country?”

At Alcatraz, Capone was assigned to a typical nine-by-five-foot cell. Unlike earlier stops in his prison career, where he received privileged treatment, that wouldn’t be the case here. No more huge private cell, home-cooked meals, telephone privileges or visits from gangland pals like Lucky Luciano and Dutch Schultz, as Chicago’s Cook County Jail had provided him. Nor would there be any silk underwear, custom-tailored suits or extra time on the tennis courts, as a sensational article by a former fellow inmate claimed he’d enjoyed in Atlanta. (The Atlanta warden denied any special treatment for Capone.)

While undoubtedly a celebrity, he was assigned to the same kind of work as any other inmate—sweeping corridors, mopping floors, doing wash in the prison laundry. Another fellow prisoner told reporters, “Al Capone gets no more privileges than the rest, except that he does not get beaten or thrown into the dungeon. He has too much political influence for that.”

Capone’s education had stopped when he was expelled in the seventh grade. (A teacher hit him, so he slugged her back, according to Laurence Bergreen’s 1994 biography, Capone: The Man and the Era.) But prison gave him an opportunity to catch up on his reading.

Biographer Eig reports that Capone’s selections from the prison library suggest a man with an interest in self-improvement, including books on the proper use of English, music appreciation and flower gardening. He also subscribed to 87 newspapers and magazines, by Bergreen’s count.

One book in particular on Capone’s reading list stands out: Life Begins at Forty, a 1932 bestseller by Walter B. Pitkin. A popular inspirational speaker, Pitkin promised that, “Every day brings forth some new thing that adds to the joy of life after forty. Work becomes easy and brief. Play grows richer and longer. Leisure lengthens. Life’s afternoon is brighter, warmer, fuller of song...” For Capone, then 36 and serving an 11-year sentence, the book may have given him something to look forward to.

Not long after his arrival at Alcatraz, Capone got the idea of starting a musical band with other inmates. He lobbied for a year before the warden relented and allowed Capone to form an ensemble, which was permitted to practice no more than 20 minutes a day.

Capone chose the banjo, Bergreen writes: “He had not previously played this or any other instrument, nor is there any evidence that he was able to read music prior to jail, but he patiently familiarized himself with the rudiments of music theory and was eventually able to decipher musical notation and to pick out a few simple tunes, softly singing along.”

Playing drums in the Alcatraz band was another prominent gangster, George “Machine Gun” Kelly, a bank robber and kidnapper better known for his virtuosity with a submachine gun.

Before long, Capone traded his banjo for a different instrument. Some biographers say it was a mandolin, but Eig notes that Capone himself referred to it as a mandola, a similar but larger stringed instrument. The added heft would have come in handy in a 1936 incident when a fellow inmate attacked Capone, then swabbing the floor near the showers, with one blade from a pair of scissors. Before a guard intervened, Eig writes, “Somehow Capone got hold of his mandola, picked it up, and swung it like a club at his attacker.”

Capone soon grew confident in his musical skills, boasting in a letter to his son that he knew about 500 songs, particularly show tunes. “Junior, there isn’t a song written that I can’t play,” he claimed. Capone also wrote at least one song himself, “Madonna Mia,” a sentimental tribute to his long-suffering wife.

Meanwhile, Capone was also suffering from syphilis, which had gone untreated for years. By the time he arrived at Alcatraz, the disease was beyond any cure, and he had begun a descent into intermittent madness.

Prison doctors tried an experimental treatment that involved injecting Capone with the malaria virus, to raise his temperature and theoretically kill the syphilis. The treatment itself nearly killed him, as did a second attempt.

In Capone’s remaining days at Alcatraz he was lucid at times and crazed at others. “His behavior became totally unpredictable,” writes Luciano J. Iorizzo in his 2003 biography, Al Capone. “Model prisoner could become raging lunatic.”

If Capone was merely biding his time in prison until he could return to his former gangland glory, that wasn’t to be. After his release from Alcatraz in January 1939, he had several months to go on his sentence, which he spent at federal prisons in Los Angeles and Lewisburg, Pennsylvania. After a brief stay in Baltimore for medical treatment, he returned to his estate on Palm Island near Miami, where he passed his days fishing, playing cards, entertaining visitors and slipping in and out of sanity. He died on January 25, 1947, eight days after this 48th birthday. His death certificate listed his occupation as “retired.”