Britain's longest-serving and first female prime minister, Margaret Thatcher, died of a stroke Monday at the age of 87. She held the post as prime minister from May 1979 until November of 1990, and during that period became well known for her uncompromising approach to political issues. "Thatcherism" became the expression used to describe the Conservative policies that were implemented during her term of office.

Thatcher was one of the most notable public figures of the 20th century and is credited for putting through reforms that helped to modernize the UK. She supported the privatization of businesses and flexible labor markets. She broke through class and gender barriers with her staunch, unique leadership style. Thatcher once said, "In politics, if you want something said, ask a man; if you want something done, ask a woman."

She embraced the nickname "Iron Lady," given to her because of her tough political stance on free market capitalism and her support of American policies.

"If you lead a country like Britain, a strong country, a country which has taken a lead in world affairs in good times and in bad, a country that is always reliable, then you have to have a touch of iron about you," Thatcher said.

Thatcher's life was depicted in the 2011 movie Iron Lady; actress Meryl Streep won an Academy Award for Best Actress for her portrayal of Britain's first female prime minister.

"She stands as an example to our daughters that there is no glass ceiling that can't be shattered," President Obama's Twitter account said on Thatcher's passing.

In 2002, Thatcher released a book dedicated to her "ideological soulmate," Ronald Reagan, called Statecraft: Strategies for a Changing World. Thatcher's doctors recommended that she not participate in public speaking, in recent years, as she had suffered from several minor strokes. Health issues kept her from attending a 2011 ceremony honoring Reagan.