On April 15, 1947, Jackie Robinson broke American baseball's color line with the Brooklyn Dodgers against the Boston Braves at historic Ebbets Field, with its "Hit Sign, Win Suit" sign. Groundbreaking. It would be two more years before President Harry Truman integrated U.S. armed forces, eight years before the U.S. Supreme Court's landmark school desegregation decision in Brown v. Board of Education, and 18 years before the passage of the 1968 Civil Rights Act.

Getting to that day was no proverbial walk in the baseball park. Robinson was threatened with lynching, spiked, jeered and called every racist epithet in the book. But along the way, his ordeal was softened by two small but powerful gestures that altered the trajectory of racial animus in America.

In 1903, a very young Branch Rickey, who in 1943 would become Dodgers president and general manager, was coaching Ohio Wesleyan's college baseball team. On a road trip to play Notre Dame in South Bend, Indiana, catcher Charlie Thomas, the lone African-American on the team, was told he couldn't stay in the hotel with his white teammates. With tears in his eyes, Thomas said, “Mr. Rickey, if I could just rub this color off me, I’d be as good as any man."

Thomas's words haunted Rickey, and he went on a mission to end the "gentlemen's agreement" that had kept black players out of baseball for 60 years. When the New York state legislature passed the 1945 Ives-Quinn Act banning race discrimination in the workplace, Rickey told his wife, “They can’t stop me now.”

But who would be the first? Jackie Robinson, a four-sport phenom at UCLA and then star shortstop of the Kansas City Monarchs in the Negro Baseball League, was on his shortlist, but Rickey fretted that he was too volatile, arrested while attending Pasadena Junior College for challenging a police stop and frisk of a black friend, and later court-martialed as a second lieutenant at Fort Hood, Texas after refusing to move to the back of the bus.

On August 28, 1945, a wary Robinson arrived at Dodger offices on Montague Street in Brooklyn Heights, suspecting that Rickey was recruiting him for a new Negro League team. But right out of the box, Rickey told Robinson, "Truth is, I think you can play in the major leagues, for the Dodgers. What about it?"

"Yes, but I want to be treated fairly,” Robinson replied. “You will not be," Rickey retorted, "before long [the N-word] will seem like a compliment," and for the next three hours, he drilled into Jackie, role-playing one infuriating scenario after another, from another ballplayer baiting him into a fight to a waiter throwing him out of a "whites only" diner. An Oscar-worthy performance.

In the end, Rickey told Robinson, "I need more than a great player, I need a man who will take abuse and insults for his race." Robinson pushed back, “You mean you want a Negro who’s afraid to fight back?” "No," Rickey barked, “I want a ballplayer with guts enough not to fight back. We can’t fight our way through this. There will be nobody on our side. Not owners, umpires, newspapermen or fans. They’ll taunt you, try to provoke a race riot in the ballpark. We can only win if we can convince the world you’re a great ballplayer and a fine gentleman. One incident, just one, can set us back twenty years.”

Robinson looked Rickey in the eye. “If you want to take this gamble, I promise there will be no incident.” After signing a contract worth $600 a month, Robinson told reporters, "I am now the guinea pig in baseball’s racial experiment."

Rickey's plan was immediately put to the test during 1946 spring training in Florida, a Jim Crow country with its laws and mores strictly segregating Blacks from Whites in schools, hotels, restaurants, buses, and every venue of daily life. Jackie and his wife Rachel had to stay in the home of a local black leader rather than the Dodgers' beachfront hotel in Daytona Beach. Jackie couldn't go out to dinner with his white teammates, and more than once a bus driver ordered, "Boy, get to the back where you belong."

After Royal's second practice in lily-white Sanford, one resident told journalists, “Folks will take matters into their hands if that ["N-word"] is not out of town by nightfall.” Not an idle threat: between 1880 and 1950 there was a lynching at least once a week in the South for some perceived breach of the racial hierarchy. At a game the next afternoon, the Sanford sheriff showed up after Robinson scored in the second inning and ordered him off the field.

The start of the regular season was a big relief because Rickey had astutely signed Robinson to the Montreal Royals rather than a minor league team south of the border. Jack Jedwab, author of Jackie Robinson’s Unforgettable Season of Baseball in Montreal: "The issue of race was not as fundamental a marker of identity in Canada as in the U.S. . . . It wasn’t an existential issue here, our conflicts centered [on] the French and English, Catholics and Protestants, . . . language and religion, not race, Canada doesn’t have the history and legally-enforced prejudice towards African-Americans found in the United States."

Rachel Robinson recalled, "When we got to Montreal it was like coming out of a nightmare, when I was pregnant the French-speaking children upstairs competed to carry my groceries and the women helped sew my maternity gowns.”

Jackie still had to win over his teammates. Opening Day, April 18, 1946. In the third inning with two men on Robinson smashed the first pitch 330' over the left field fence. As he circled the bases, pitcher Barney DeForge and outfielder Marv Rackley crossed home in front of him, and rather than waiting to congratulate him at home plate, they turned heel toward the dugout.

But waiting in the on-deck circle was left fielder George "Shotgun" Shuba, who earned his nickname by spraying line drives to all fields like buckshot. As a jubilant Robinson crossed the plate, George extended his hand, "That’s the way to hit that ball, Jackie, that’s the old ballgame right there." A simple but powerful gesture.

That night, Jackie called Shuba to thank him, saying he had worried that his white teammates wouldn’t shake his hand. George replied, “Why? Aren't you on our team? Didn't you just win the game for us? Well, ok, then.” "That day the dam burst between me and my teammates,” Robinson said in his 1972 memoir, I Never Had It Made, "and it generated a tremendous power and drive in me.”

On April 11, 1947, after Robinson's terrific '46 season with the Royals, Rickey signed him to a $21,000 major league contract with the Dodgers. But if Rachel expected another Montreal, she would have a rude awakening. She and Jackie were about to free-fall into American cities being transformed by the Great Migration:

Until 1910, more than 90% of all African-Americans lived in the South. But in the winter of 1916, the migration began, like the flap of a seagull’s wings, as a rivulet of black families escaping Selma, Alabama. Their quiet departure was scarcely noticed except for a single paragraph in the Chicago Defender, to whom they confided that "the treatment doesn’t warrant staying.

The rivulet would become rapids, which grew into a flood of six million people journeying out of the South over the course of six decades. They were seeking political asylum within the borders of their own country. . . . Until that moment and from the time of their arrival on these shores, the vast majority of African-Americans had been confined to the South, at the bottom of a feudal social order, at the mercy of slaveholders and their descendants and often violent vigilantes. The Great Migration was the first big step that the nation’s servant class ever took without asking.

(Isabel Wilkerson, The Long Lasting Legacy of the Great Migration, Smithsonian Magazine September 2016)

It was one of the largest migrations in history, greater than those of the Irish, Italians, Poles or any other ethnic group into the United States. By the 1970s, almost half of all African-Americans, six million in all, were living outside the South, most of them in New York, Philadelphia, Cleveland, Chicago, Los Angeles and other large northern and western cities.

This great influx of "foreigners" roused deep-seated racial fears and hostility that had lingered beneath the surface when African-Americans in relatively small numbers were mostly out of sight, out of mind. Now, one community after another erected exclusionary barriers, starting with a proliferation of restrictive covenants that prevented African- Americans from buying or renting a property in white neighborhoods, and so their schools too were segregated de facto if not by law. The message: Come if you will, but not to our neighborhoods, not in our schools, not near our daughters.

Baseball reflected the country at large. In January 1947, the 16 major league owners voted 15 – 1, Rickey the only nay, against allowing Robinson to join the Dodgers. Fortunately, Rickey had a crucial ally, new baseball commissioner Albert "Happy" Chandler, former Kentucky governor and a strong civil rights advocate, who vetoed the vote and laid down the law, "If they can fight and die on Okinawa and Guadalcanal, they can play ball in America."

But it wasn't just the owners. The St. Louis Cardinals and several other teams threatened to strike if Robinson played. Closer to home, five Dodger veterans, Dixie Walker, Hugh Casey, Kirby Higbe, Carl Furillo and Bobby Bragan, all from the South, signed a petition to keep Robinson off the roster, they didn't want a black man as a teammate. Higbe, the grandson of a Confederate soldier, boasted that growing up in South Carolina he built up his pitching arm by throwing rocks at black children.

Feisty Dodger manager Leo Durocher wasn't what having it, “I don't care if the guy . . . has stripes like a . . . bleepin' zebra,” he told his players, “I say he plays. And if you don't like it, I will see that you are all traded.” And they were. When a defiant Higbe demanded a trade, two weeks later he was out the door, Casey a few months later and then Walker.

Robinson soon won his teammates' respect and acceptance. When the Dodgers played the Philadelphia Phillies, manager Ben Chapman jeered at Robinson, ”Hey, you black [expletive], why don’t you go back to the cotton fields where you belong?” Philly players and fans piled on, calling him "shoeshine boy" and "snowflake." Jackie's teammates rallied to his defense, Eddie Stanky yelled at the Phillies' dugout, ”Listen, you yellow-bellied cowards, why don’t you yell at someone who can answer back?”

Robinson endured an onslaught of racial abuse, opposing pitchers threw at his head, and base runners went out of their way to spike him. More sobering were the unambiguous death threats, not just against Jackie, but Rachel too, even Jackie, Jr. It ate Robinson alive, he had chronic stomach pains and his hair began to grey. Jimmy Cannon of the New York Post wrote, “There is a great lynch mob among us and they go unhooded and work without rope.” Anonymous, cowardly trolls were around long before the internet.

But eventually, the tide of racism slowly began to ebb, starting in a late-season game at Crosley Field in Cincinnati. As the Reds bench and fans shouted racist epithets, Kentuckian Pee Wee Reese, Dodger shortstop and captain, walked across the diamond and put his arm around Robinson's shoulder, quietly talking to him. The ballpark was hushed. A simple human gesture stopped the abusers in their tracks. Years later Robinson told the author "Boys of Summer" Roger Kahn: “After Pee Wee came over like that, I never felt alone on a baseball field again.”

George Shuba? In 1948 he was called up to the majors and reunited with Robinson for seven Dodger seasons, and in 1953 was the first National Leaguer with a pinch-hit homer in a World Series.

Before he retired at the end of the 1957 season, Robinson would hit 137 home runs and steal 197 bases, helping the Dodgers win five National League pennants and the 1955 World Series. He was inducted into the Baseball Hall of Fame in 1962.

In July 1947, Larry Doby crossed the color line in the American League, followed the next year by pitcher Satchel Paige, barred from the majors until he was 42, the oldest rookie ever. Between 1949 and 1960, black players had 9 out of 12 Most Valuable Player awards in the National League, But it took a decade for some teams to catch on. By 1954, five years after Robinson broke in, only six major league teams had a black player, the Boston Red Sox didn't have one until 1959, prejudice trumping wins and titles.

Robinson was never offered a manager or coach job in major league baseball. Instead, he became a vice president for Chock Full o' Nuts, founded Freedom National Bank, formed Robinson Construction to build low-income family housing and dove headfirst into the civil rights movement.

He decided, “If I had a room jammed with trophies, awards and citations, and a child of mine came into that room and asked what I had done in defense of black people and decent whites fighting for freedom, and I had to tell that child that I had kept quiet, that I had been timid, I would have to mark myself a total failure at the whole business of living."

Robinson was in the front rank of many civil rights marches, including the August 28, 1963, March on Washington, and was on the dais when Martin Luther King, Jr. delivered his "I have a dream" oration. King said of Robinson, "I didn't start the Civil Rights Movement, Jackie Robinson did. . . . He underwent . . . the loneliness [of] a pilgrim walking through the lonesome byways toward the high road of freedom . . . a sit-inner before sit-ins, a freedom rider before freedom rides.”