Mary Wells Lawrence, the trailblazing Mad Men creative icon and agency owner, died on Saturday in London at the age of 95.

According to an obituary in The New York Times, Lawrence’s daughter Katy Bryan verified her death.

For a time, Wells Lawrence was the highest-paid female executive on Madison Avenue. She is supposed to have inspired the Elizabeth Moss character in the AMC television series “Mad Men,” which aired from 2007 to 2015.

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When she was passed over for the leadership of Interpublic-owned ad firm Tinker & Partners, she departed in 1966 to start her own business. Dick Rich and Stewart Greene, two colleagues she worked closely with at the agency, have also resigned. They founded Wells Rich Greene.

At Tinker, the trio helped create the spectacular “Alka-Seltzer On The Rocks” campaign, which included the memorable jingle “Plop-plop, fizz-fizz, oh, what a relief it is!”

They are also credited with coordinating a thorough brand makeover for Braniff Airlines, which included changing flight attendant uniforms and introducing vibrant colors to the company’s drab fleet of commercial jets.

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According to the Times obituary, Wells Lawrence became the first female CEO of a firm listed on the New York Stock Exchange while working with Wells Rich Greene (with Braniff as its first client). The agency went public in 1968.

One of the agency’s most well-known ads was “I Love New York,” which debuted in 1977, when the city was at its lowest moment, with rampant crime and on the verge of financial disaster.

At its peak, the firm generated $885 million in billings for customers including IBM, Procter & Gamble, Ford, Hertz, and others.