During a recent Saturday morning rehearsal of the Commonwealth Youthchoirs, co-founder Steve Fisher uses a microphone to give directions that cut through the soupy, low-level hum of noise. The acoustics of the limestone-lined chapel at Girard College can be tricky. Fisher compares the space to “a canyon with sound bouncing around.” Though not all of the 350 kids who will sing “The Children’s March”—a work about the children of Birmingham who faced off against the authorities in 1963 to protest segregation—are present today since it’s the day before Easter, there are enough here to make that mic a godsend.

Fisher introduces two older Youthchoirs alumni who will sing the parts of Bull Connor, the Birmingham Commissioner of Public Safety who authorized the use of firehoses and dogs on the marching children, and Martin Luther King Jr., the legendary minister and civil rights hero.

Fisher, like a choral ringmaster, does a slow turn to verify all eyes are on him as he announces Andrew Shaw as the villainous Connor. The chapel’s occupants—from ages 8 to 18—erupt in an enthusiastic blanket of booing. Next up, Fisher announces Nicholas Trawick as Dr. King. Cheers of approval swell up to the ceiling of the 1,700 seat venue. The kids are into this, which is exactly what Fisher wants.

He also calls forward two 9-year-old singers to stand up so the others can visualize just how young 9 really is. Fisher reminds everyone that protestors as young as this pair of volunteers spent a week in jail alone, without their parents, under Bull Connor’s directives. By now, the kids are familiar with this dark chapter of American history, but a rumble of disapproval sweeps through the chapel. Despite the limited practice time, the director peppers the three-hour rehearsal with educational nuggets like this.

Knowledge is power, as the saying goes. Learning the musical score and lyrics is only part of the process. Fisher wants the 350 kids singing in the May 2 performance of “The Children’s March” to learn the lessons of the past and understand the power they possess. Understanding the work’s context is a critical component in his mission to educate these gifted singers.

“This work reminds our children of the power of standing up for something they believe in,” says Fisher by phone in a separate interview. “It also reminds the adults that children have a lot of power. We tend to say kids are too idealistic or say, ‘You don’t understand how the world works,’ but back in 1963, when those kids marched against segregation, their idealism worked to everyone’s advantage.”

Sometimes idealism is the antidote to jaded, worldly resignation. Since January, we’ve already begun to see the resurgence of street protests and a reawakening of ordinary citizens to grassroots political movements. Some moments, such as Birmingham in 1963, cry out for people willing to take major risks.

During the 1960s, Birmingham, Alabama, was home to some of the most vicious segregation in the country. By April of 1963, the efforts by Martin Luther King and the Southern Christian Leadership Conference (SCLC) to force desegregation with sit-ins and non-violent marches were stalling out. Even King’s arrest on Good Friday was not enough to galvanize the national conversation. African-American adults were becoming uneasy to protest for fear of arrests in the increasingly menacing climate, and of losing the small gains they’d made on jobs and home ownership.

“This work reminds our children of the power of standing up for something they believe in,” says Fisher. “It also reminds the adults that children have a lot of power. We tend to say kids are too idealistic or say, ‘You don’t understand how the world works,’ but back in 1963, when those kids marched against segregation, their idealism worked to everyone’s advantage.”

Who would step into the breach? Students were recruited and trained by the SCLC for peaceful protest. Many children defied their parents and marched without permission. Thousands of courageous kids left the 16th Street Baptist Church on May 2 and changed history that week. Children were arrested. Some remained in jail for more than a week. Some children had firehoses turned on them by firefighters. Some children had police dogs set on them by police officers. The nation was appalled by the coverage that appeared on television. And Birmingham began its grudging forward movement into desegregation.

Fifty-four years to the day of Birmingham’s Children’s Crusade, Commonwealth Youthchoirs performs this hour-long chorale piece—a mix of song and narration—originally commissioned by the Philadelphia avocational chorus, Singing City, at Girard College. Written by local composer Andrew Bleckner, the piece is narrated by its librettist, Charlotte Blake Alston, who many may know from her work with the Philadelphia Orchestra’s “Sound All Around” and Family concert series as a beloved storyteller.

Commonwealth Youthchoirs is the non-profit umbrella organization that comprises Keystone State Boychoir, Pennsylvania Girlchoir, Find Your Instrument! and Good Morning Music! (for ages pre-K to grade 2). Locals may remember the Keystone State Boychoir for grabbing headlines when singer Bobby Hill flawlessly sang an impromptu solo for Pope Francis during his 2015 visit. KSB is the senior branch of CY, getting its start back in 2001.

Commonwealth Youthchoirs was awarded a National Endowment for the Arts grant to stage this work, with the stipulation that the young singers understand the legacy of the famous march. Fisher brought in speakers to help the children make sense of the violence expressed in the piece. As part of that education, local civil rights activist and singer, Kenneth “Freedom Smitty” Salaam, met with the children to talk about his experiences as a freedom fighter back in the 60s.

Salaam walked with MLK in 1965 when the pastor visited Philadelphia to support Cecil B. Moore’s efforts to desegregate North Philly’s Girard College. The school was founded by philanthropist Stephen Girard in 1848 as a boarding school that offered free tuition to white orphans or fatherless boys. Salaam, King, Moore and others “walked the walls” around the school to protest the exclusion of black boys. Partly as a result of the protest, Stephen Girard’s will was eventually broken and the school started admitting African-American boys in 1968. (Girls did not matriculate until 1984.)

Now, as the clock winds down on this Saturday morning rehearsal—only a little more than two weeks until showtime—Fisher moves through his rehearsal notes with focus and intensity, cueing the various groups of singers stationed around the large chapel in a process he calls “messy” but productive. Despite the stopping and starting of music, when the young voices unite, even briefly, they pierce the acoustics, creating a visceral charge. The sound of the children’s voices is poignant and powerful.

The singers, many wearing hoodies, jeans and sneakers and quietly fidgeting in their pews, get signaled by Fisher to practice the line: “You got a right to the tree of life…” Each group runs the line as the director points to them, one after another. One wonders if these kids will engage as deeply about politics and issues as their counterparts from 1963. If knowledge is power, then they are armed and ready.

“There’s still a need to march and protest,” says Fisher. “Things still aren’t equal for everyone.”

“The Children’s March,” Tuesday, May 2, 7 p.m., Girard College Chapel, 2101 S. College Avenue, Philadelphia. cychoirs.org/childrensmarch