William H. Gates Sr., a founding member of what is now K&L Gates, the father of Microsoft co-founder Bill Gates and a leading lawyer and philanthropist in his own right, has died at 94.

“It’s an especially sad day for us at K&L Gates as we grieve the loss of a man whose name remains a prominent part of our firm’s own name,” K&L Gates global managing partner Jim Segerdahl said in a statement late Tuesday night. “When Kirkpatrick & Lockhart Nicholson Graham combined with Preston Gates & Ellis more than a dozen years ago, it was an easy decision to maintain the Gates name in recognition of the vast contributions Bill had made—and would continue to make—as a lawyer, humanitarian and philanthropist, and in light of his high standards for professional excellence and integrity.