AOL celebrated becoming the first tenant to occupy Boston’s old Filene’s site, moving into the renovated Burnham Building.

The Boston Business Journal reports AOL’s tenancy became official Monday morning, when the New-York based company moved in “about 50 employees” to the sixth floor of the renovated building, which is part of Millennium Partners’ nearly $700 million redevelopment plan for the site. Previously, AOL’s Boston operations were being conducted out of office space at 2 Oliver St. in the Financial District, the BBJ reports.

Related: Millennium Tower Boston construction photos

Next Monday, August 25, according to the BBJ, Arnold Worldwide and Havas Media will move 600 employees into approximately 125,000 square feet of Burnham Building space, located at the corner of Washington and Summer Streets, atop the DTX MBTA station.

On June 30, construction commenced on Boston’s flagship Roche Bros. location, at the Millennium Tower site. The Roche Bros. is expected to occupy 25,000 square feet, across two floors, inside the old Filene’s Basement.

Roche Bros. renderings:

Renderings courtesy of Roche Bros.