HENDERSON — David Rousseau stood, walked to the center of the hallowed square and took his turn leading a three-centuries-old tradition.

“I’m 86, and I’ve been doing it all of my life,” Rousseau said before the start of the 164th East Texas Sacred Harp Singing Convention in Henderson.

Moments later, the Henderson Civic Center was enveloped in the harmonious sound of more than 100 singers.

Sacred harp is a religious folk music sung with the aid of a unique shaped-note songbook first published in 1844, but its North American roots date back to the late 18th century. Unlike the classical, more popular 7-note style of “Do, re, mi, fa, so, la, ti,” sacred harp uses the four syllables of “fa, sol, la, mi” for its musical scale.

“Don’t ask me why it’s that way. It is,” Rousseau said. “We’re carrying on a tradition, as you can tell, and anyone who is interested is welcome, and we’re always very open with it.”

Rusk County has hosted a sacred harp convention since 1855, minus a four-year period during the Civil War. As with every year, admission is free to the two-day event, and anyone is invited to lead a song, including young children.

Rousseau believes he was about 6 months old when he was brought to his first sacred harp convention.

“It’s a lifetime thing,” he said. “I’m fourth generation who sings it — not that I’m good, but we do what we can.”

The convention attracts enthusiasts from across the U.S. and around the world, including the United Kingdom, Bolivia and Mexico, Rousseau added.

Tommie Spurlock, of Ozark, Alabama, has been attending for 35 years, though he’s missed four times — twice for being sick, once for the funeral of his eldest sister’s husband and once for his grandson’s wedding.

“At the reception party, all of the grandparents had to give a speech … I got up and said, ‘Son, you better make this stick. You know you caused your papaw to miss his trip to East Texas to the singing convention,’” Spurlock said with a chuckle, “so they’re still hanging on.”

Spurlock makes the annual pilgrimage to see everyone and “the singing is just so good. Of course, a lot of the older ones that we knew back years ago when we started coming have gone on.”

William Smith and William Little developed the shaped-note method iconic of sacred harp in the early 1800s. It was a method that made reading lines and spaces and recognizing sharps and flats unnecessary.

Glenda Lazenby of Woodville said sacred harp had its earliest beginnings in Elizabethan England — information she learned from her husband, Jim, who wrote his master’s thesis on the subject in 1971.

“I would characterize this music as having drive, full-throated, primitive, some would say, but it’s characterized by open chords,” she said. “It was devised as a way to teach illiterate people how to get the pitch of a song, and they used the shapes and somewhat the position of the staff came later, but it is very indigenous to America.

“The patterns are different. The meter is different. This is the form that is kept until this day,” she said.

There are other sacred harp conventions, but Rousseau calls the East Texas event the apex because of its history. It is the oldest known singing convention in Texas and second-oldest continuous sacred harp convention in the U.S.

This year’s convention continues 9:30 a.m. until 2:30 p.m. today at the Henderson Civic Center.

“Again,” Rousseau said, “anyone is welcome.”