Mary Wells Lawrence, an advertising pioneer, has died at the age of 95

She became the first woman to own and operate a major national advertising agency. Her company, Wells Rich Greene, was best known for its "I ♥ NY" campaign.

She added jazzy colors to the Braniff airliners. She added "plop plop, fizz fizz" to Alka-Seltzer. She warned Benson & Hedges smokers that long cigarettes could burst balloons or set beards on fire. And from Niagara Falls to Broadway, she appealed to millions with her "I ♥ NY" campaign.

Mary Wells Lawrence, raised in Ohio, took her imagination and ambition to New York at 22, where she broke through the male bastions of 1960s advertising, quit a prestigious job when she was denied the presidency, started her own agency and wowed Madison Avenue with striking campaigns that entered American culture. She died Saturday morning in London. She was 95 years old.

Her death was confirmed at the hospital by her daughter Kathy Bryan.

Ms. Wells Lawrence was the first woman to own and operate a major national advertising agency, Wells Rich Greene, and the first female CEO of a company listed on the New York Stock Exchange. In the 1970s, she was considered the highest paid executive in the industry with a salary of over $300,000 (over a million dollars in today's currency).

She was "perhaps the most influential and successful woman ever to work in advertising", Stuart Elliott, then an advertising columnist for The New York Times, wrote in 2002 about Ms. Wells Lawrence, who sold her agency for $160 million (about $385 million today) and retired in 1990.

The world of advertising has changed a lot since then. Most agencies that nurtured creativity and made commercials with catchy music, talented actors, clever lyrics and nimble strategies to strengthen brands and products have long since given way to corporate giants led by executives not directly involved in the production of advertising, which relies heavily on market research and picturesque digital gimmicks.

But in a pioneering career spanning four decades, including 24 years as her own boss, Ms. Wells Lawrence and her colleagues Dick Rich and Stuart Green created practical campaigns that challenged orthodoxy, took risks and, with wit and insight, often turned old-fashioned salesmanship into entertainment. Sometimes they radically changed public opinion.