This post has been updated.

White House Curator William Allman is retiring June 1 after a 40-year career, the White House announced on Tuesday.

“It has been a tremendous honor to serve eight Presidents and First Ladies in helping to preserve and beautify the White House, and maintain and interpret its wonderful collections of art and furnishings,” Allman said in a statement. “As a steward of the museum component of an ever-evolving and ever-bustling home and office, I truly have had a dream job.”

News of Allman’s impending departure, which was first reported by CNN, comes on the heels of the dismissal of Chief White House Usher Angella Reid and leaves vacant two senior positions on the White House’s permanent staff.

Allman is responsible for preserving and protecting thousands of pieces of art, furniture and decorative objects in the White House’s collection. He has been a touchstone for first families since 1976. He also helped the Trumps navigate their first months in the executive mansion.

Stephanie Grisham, the spokeswoman for first lady Melania Trump, said Allman had thought about retiring last year but was “kind enough” to stay on the job during the transition. “We thank Bill for all of his dedicated service and wish him the very best in his retirement,” she said in a statement.

Allman’s friends and associates said he has been planning to step down for a while and his departure is not connected to Reid’s sudden dismissal by the Trumps.

“He has been thinking about this for a long time,” said Michael Smith, who worked as interior designer to the Obamas and collaborated with Allman on many projects, including the refurbishment of the State Dining Room. “It’s an incredibly intense job. You are dealing with a family that is living in a building that is part private house and requires privacy and solitude. So you are trying to protect that family while you are operating an active museum and tours and dealing with people at Christmas parties where they can sit on the furniture and have food and drinks in these historic rooms.”

Allman worked closely with the two previous first ladies, who both sought to put their imprint on the house. Laura Bush collaborated with Allman on the restoration of the Lincoln Bedroom, combing through historic details to restore it. Michelle Obama, along with Smith, updated the Family Dining Room with Allman’s help by adding modern art and restoring the furnishings.

Allman, who could not be reached for an interview, had always planned to stay on long enough to help the Trump family through their first days in the White House before stepping away from the job, said one associate. He has held the top job in the curator’s office since 2002 and became well known in D.C. circles.

He is a native of Bethesda and holds degrees in history and American Studies from the University of Maryland and George Washington University.

“His departure means the White House is losing its institutional memory in terms of the history of the house,” said Betty Monkman, who served as White House curator from 1997 to 2002 and worked with Allman for many years.

The Trumps will now be tasked with appointing Allman’s replacement.