Longtime city government aide Ronald R. Collins has retired from his post as director of the Office of Boards and Commissions.

Collins, well-known as an encyclopedia of city history and government, worked for at least a half dozen agencies in the city government, from Fire and Emergency Medical Services to Human Services to Boards and Commissions, over the years.

He headed Boards and Commissions, which requires the recruitment and vetting of candidates for hundreds of appointments, under former mayor Anthony A. Williams and held the position again under Mayor Vincent C. Gray (D).

Last year, the mayor’s administration was criticized for filling vacancies slowly and for the poor vetting of some nominees. Gray revealed at that time that Collins was dealing with an illness.

Pedro Ribeiro, Gray’s director of communications, confirmed that Collins retired this week, but he declined further comment, citing personnel rules.

Ribeiro said an interim director has not been chosen.

Collins, 57, could not be immediately reached for comment.