(CNN)Their names were burned into the pine plywood casket Billy Graham was laid to rest on Friday.
"Hand crafted by Richard Liggett, Paul Krolowitz, Clifford Bowman."
They were hardened inmates at Louisiana State Penitentiary. In 2006, they built the plain wooden casket that would one day be lowered into the Charlotte, North Carolina, ground at the burial service for the globe-trotting preacher and spiritual confidant to American presidents.
More than 2,000 people attended Friday's private service for Graham, who was 99 when he died February 21 at his home in Montreat. Among the guests were President Donald Trump, the first lady and Vice President Mike Pence and his wife, Karen.
After the service at the Billy Graham Library, the Protestant preacher was buried beside his wife, Ruth, at the foot of the cross-shaped brick walkway in the library's Prayer Garden.
The caskets came courtesy of one of Graham's sons. In 2005, his eldest son, Franklin, was struck by the "simple and natural beauty" of the wooden caskets during a visit to the penitentiary, according to a post on the website of the Billy Graham Evangelistic Association.
The largest maximum security prison in the world, the complex is also known by the name of the plantation that previously occupied its grounds, Angola, itself a reference to the home country of many of its enslaved African workers. The sprawling prison is the size of Manhattan and surrounded on three sides by the Mississippi River.
Franklin Graham, impressed with their handiwork, asked the men at the carpentry workshop to build two caskets for his parents, according to the association.
"I liked the simple coffin with a cross on top," he told the inmates.
The caskets were lined with a white mattress pad. A wooden cross was nailed on top. They cost about $200 each to make.
"We were down there for a prison rodeo and my father had seen these caskets being made," Franklin Graham's son, Roy, said in a video posted on social media.
"He came back and told my grandmother he bought her gift. He bought her a casket made by prisoners. And my grandmother thought it was outstanding."
Angola inmates had started building the caskets after the warden at the time saw that poorer inmates were being buried in cardboard boxes, according to the association's post.
"The prisoners are people who need forgiveness, too," Roy Graham said in the video. "And that's what my grandmother loved about it. We all need forgiveness.''
Franklin Graham returned to Angola in 2008 for the dedication of a chapel constructed by prisoners and funded with private donations, according to the association. Angola, once one of the most violent prisons in the country, now has a seminary.
The three Angola prisoners handcrafted the caskets.
Liggett and Bowman, both convicted of murder, have died, according to assistant warden Gary Young. Krolowitz, who did time for armed robbery, has since been released.
"They crafted these caskets in a very dignified and humble manner," Young said.
A prison chaplain recalled that Liggett, who was known as "Grasshopper" and died in 2007, had told him: "Billy Graham is a simple man who preached a simple message. He must be buried in a simple casket."
Ruth Bell Graham was buried in 2007 in a casket handcrafted by the Angola inmates. Billy Graham was laid to rest Friday beside her grave in his own unique casket.