A nine-month project to restore the 5,400-square-foot ceiling of the Old South Meeting House in Boston’s Downtown Crossing has begun.

Wendall Kalsow, president of Somerville-based McGinley Kalsow and Assoc., will direct the project with assistance from David Riccio of Canning Studios in Cheshire, Connecticut. As part of the project, base paint dating back to 1899 and subsequent layers will be removed. Ceiling repainting will begin after the Boston Tea Party reenactment in December, with a projected completion date of March 2017. Exhibits will remain open during the facility’s normal public visiting hours.

Millennium Partners of New York, developer of the nearby 685-foot-tall Millennium Tower Boston, contributed $112,500 toward the project. The Massachusetts Cultural Facilities Fund awarded $95,000. The Cultural Facilities Fund is jointly administered by MassDevelopment and the Massachusetts Cultural Council.

The 1729 meetinghouse was a central gathering spot in colonial Boston including meetings to protest the Boston Massacre in 1770 and plan the Boston Tea Party in 1773.

“Boston’s Downtown Crossing and the adjacent historic Ladder District are central to Boston’s attractiveness. We believe in sensitively adding new elements to the old urban core in a strategic way, and that means respecting and protecting structures of the past,” Millennium Partners Principal Kathleen MacNeil said in a statement.