Brooklyn Museum Director Arnold L. Lehman announced yesterday at the fall meeting of the Board of Trustees that he will retire in mid-2015.

Lehman, who turned 70 in July, joined the Brooklyn Museum as its director in September 1997.

Under his leadership, the Brooklyn Museum- one of the oldest and largest museums in the country- has undergone nearly two decades of sustained growth, more than doubling its audience and its endowment, refocusing attention on the visitor, expanding and significantly enhancing its landmark building, re-envisioning and re-installing much of its permanent collection, developing a dynamic exhibition program for its Brooklyn site as well as for its national traveling exhibitions, pioneering new technology and, overall, renewing the commitment of a world-renowned institution to its metropolitan area community of artists, families and young people.