Two perennial New York deal-making firms, Cravath, Swaine & Moore and Simpson, Thacher & Bartlett, were called in to oversee legal negotiations for the largest-ever merger, this week’s estimated $150 billion acquisition by America Online Inc. of media and entertainment giant Time Warner Inc. Cravath is representing Time Warner and Simpson Thacher is primary counsel to AOL, along with the Internet company’s longtime outside general counsel, Boston’s Mintz, Levin, Cohn, Ferris, Glovsky and Popeo P.C.

The Simpson Thacher attorneys representing Dulles, Va.-based AOL are partners Richard I. Beattie, Philip T. Ruegger, David J. Sorkin, Kenneth C. Edgar, Steven C. Todrys and Kenneth R. Logan; and associates Peter S. Malloy, Patrick J. Naughton, Christopher B. Lee, Jonathan A. Kaye, Eric M. Swedenberg, Spencer A. Lehv, Rae Terry, Malika S. Hinkson, Christopher J. Vauthy, Lawrence M. Moss, Katharine P. Moir and Peter E. Kazanoff.