(CNN) -- Ernest Miller Hemingway grew up during a time of great change in America. It was the turn of the century, a period which saw much collision between old world idealism and new world possibilities.

Hemingway was born on July 21, 1899, in Oak Park, Illinois, a well-to-do township near Chicago. He was the second child of Grace Hall and Clarence Edmonds Hemingway in a family that would eventually include four girls and two boys.

While there are stories that Hemingway had a troubled childhood, the early seeds of a writer were evident and nurtured.

His father was a doctor who interested Ernest in sciences and objective reasoning. Ernest's mother taught music and made sure her children were well-schooled in the arts.

Both parents were involved in their church, giving their children a strong foundation in religion, morals and values.

"He really grew up with a rich environment of culture, religion and the sciences," says Redd Griffin, a historian and board member of the Ernest Hemingway Foundation of Oak Park.

The Hemingway family, just before Ernest left for Italy in 1918. Pictured are Dr. Hemingway, Grace, Ernest, Madelaine (Sunny), Ursula, Marcelline. Leicester and Carol are in front. Click on photo to link for large version.

Even in his early years, Hemingway provoked varied responses from the people around him.

"There are those here who said he could be a bully," Griffin says. "People here, either they loved him or hated him; there was no in between. He had that effect on people."

Young Hemingway was also an avid explorer, heading to nearby woods for hikes and fishing expeditions with boyhood pals.

"I think he always wanted to explore ... I think there was a restlessness in him," says Griffin.

There were also the summer treks to Michigan, which became the basis for later stories, including "Big Two-Hearted River."

After being wounded in battle, Hemingway stayed at the American Red Cross Hospital in Milan, Italy. Photo taken September 1918.

The writer in Hemingway was also taking form. In school, Hemingway penned stories that are now forgettable, but show raw talent.

"His themes were almost always read aloud in class as examples of what we should all strive for," remembered Susan Lowery, a high school classmate.

After graduating from high school, Hemingway moved to Kansas City to work as a cub reporter for the Star, covering the local beat that included fires, work strikes and crime. His stay there lasted from the fall of 1917 to the spring of 1918, but he cited the experience as invaluable.

Years later, Hemingway would point to the Kansas City Star stylebook as the guideline he had followed throughout his literary career. It instructed its writers to use "short declarative sentences," something Hemingway would trademark in his streamlined prose.

On Hemingway While recovering from being wounded on the Italian front in World War I, Hemingway picked 227 metal fragments out of his right leg.

In 1918, Hemingway left the Star to volunteer in World War I as an ambulance driver for the Red Cross. He was wounded in both legs by mortar and machine-gun fire, and while recuperating in a hospital in Milan fell in love with a nurse.

Agnes von Kurowsky, an American-born 26-year-old, was 7 1/2 years older than Hemingway and had a reputation for being a flirt. She was extremely popular with the male patients.

Hemingway, a friend to her at first, eventually fell under her spell, and she too seems to have had feelings for Hemingway.

Agnes von Kurowsky was Hemingway's inspiration for the character Catherine Barkley in his novel "A Farewell to Arms"

The relationship is a focus of debate for many scholars -- some believe it was a serious love affair, but others maintain it bordered on a crush for Hemingway. Regardless, the experience eventually led to Hemingway's classic "A Farewell to Arms," (1929) which many critics point to as his best work.

The story revolves around a World War I ambulance driver who is injured in action and falls for his nurse. It has a tragic end, reflecting the Lost Generation's post-war disenchantment.

In reality, Hemingway returned to the States a war hero ("the first American casualty in Italy"), decorated for his courage and the injuries he suffered. But he was not able to keep Agnes' affections.

Although they kept in touch with each other throughout their lives, Agnes ended the affair with a letter that read in part, "I can't get away from the fact that you're just a boy -- a kid ... ."

"Then -- & believe me when I say this is sudden for me, too -- I expect to be married soon."

Hemingway with Hadley in Oak Park, 1921

Hemingway was heartbroken, but he moved on. Living in Chicago, writing freelance pieces, he met the wealthy Hadley Richardson through literary friends. They were married in 1921.

He also became acquainted with writer Sherwood Anderson, who told Hemingway that if he was serious about becoming a novelist, he should move to Paris and live among the expatriate writers there. Hemingway and Hadley were soon on a boat to Europe, with letters of introduction to the likes of Gertrude Stein and Ford Madox Ford.

It's easy to wonder what might have become of Hemingway if he never ventured to Paris. His time spent there was perhaps the greatest apprenticeship of any 20th century artist.

On Hemingway While living in Paris in the early '20s, Hemingway and his first wife, Hadley, were to rendezvous in Switzerland for a skiing trip. Hoping her husband would work on his short stories, Hadley packed up Hemingway's literary works, originals and carbons, and put them in a suitcase. She left the suitcase unattended while on a train, and it was stolen. The manuscripts were never recovered.

"If he hadn't been in Paris when he was, I'm not sure he would have turned out to be the Hemingway we know," says Michael Reynolds, author of several Hemingway books, including "Hemingway: The Paris Years." "Between January of '22 and April of '24 he transformed himself."

The Hemingways paid the bills with Hadley's trust fund and with work Ernest did for the Toronto Star. In his free time -- when he wasn't spending idle hours at Paris cafes or traversing the European countryside -- he worked on his fiction, and blossomed under the guidance of Stein, Ford, Ezra Pound, F. Scott Fitzgerald, and James Joyce.

Hemingway with his first son John, nicknamed "Bumby," in Paris, 1924

In 1923, Hemingway was published. His collection "Three Stories and Ten Poems" was printed in Paris by Robert McAlmon. It was also during this time that Hemingway became a father, his wife giving birth to a boy named John Hadley Nicanor, who was nicknamed "Bumby."

In 1924 and 1925, two versions of "In Our Time" were published, a collection of stories featuring Hemingway's alter-ego, Nick Adams. At this time, Hemingway was also forming one of literature's most interesting friendships with Fitzgerald, author of the 1925 classic "The Great Gatsby."

The two made an unlikely pair -- Hemingway still developing into the man's man, with a sharp writing style; and Fitzgerald, the soft romantic whom Hemingway would later reduce to a sexually insecure man, who was infatuated with the rich.

But there seemed to be a collective effort by Hemingway's many writer-mentors to witness the birth of his first novel.

Hemingway's trip to Spain in the summer of 1925 would live forever in his novel "The Sun Also Rises." Here, Hemingway, left, sits with Lady Duff Twysden (inspiration for the character Brett Ashley), Hadley and others at the Festival of San Fermin in Pamplona, Spain in July 1925.

It came in 1926, and Hemingway's life would never be the same. "The Sun Also Rises" was an international success. The story, based on Hemingway's own experiences, chronicled a group of American expatriates living in Paris who travel to Pamplona, Spain, for the San Fermin Festival, or "the running of the bulls."

Although Hemingway's career was taking off, his personal life was showing cracks. Hemingway had begun an affair with Pauline Pfeiffer, a close friend of both Hadley and Ernest. By 1927, Hadley would divorce Hemingway, who would promptly marry Pauline.

Hemingway was also cutting his ties with the Paris group that helped him.

"I think Hemingway had some significant strengths as a writer and human being, but he also had profound weaknesses," says Hemingway scholar Dr. James Nagel. "One of his weaknesses is that he seems not to have been very good at feeling gratitude. He tended to turn his back on people who helped him.

"He turned his back on the Paris group," Nagel says.

In the next year, Hemingway and Pauline would settle in Key West, and Hemingway would attempt to build on his reputation as one of America's preeminent writers.