These nurses influenced history in ways you might not have realized

National Nurses Day is observed annually on May 6, honoring the achievements and selflessness of nurses and their impact on society.

The day kicks off a full week honoring nurses, culminating on May 12, Florence Nightingale's birthday. After a proclamation by President Nixon in 1974 to create a "National Nurses Week," a resolution was initiated by the American Nurses Association to make May 6 National Nurses Day, which was recognized by the U.S. Congress and officially signed by President Ronald Reagan in 1982.

Throughout history, nurses have played a critical role in communities and have been interwoven into the fabric of society for centuries. Here are some of the most influential nurses who dedicated themselves to the world and the care of others in ways you might not have realized.

Florence Nightingale - During the Crimean war in 1854, Florence Nightingale and a team of nurses were directly responsible for improving conditions at a British military hospital in which more people were dying from diseases due to unsanitary conditions than from actual battle wounds. Known as the "Angel of Crimea," her work reduced the hospital's death rate by two-thirds.

Nightingale was born into a wealthy family where she defied expectations of the time and pursued a career in nursing. In 19th century Great Britain, women of the upper class were expected to marry to ensure class standing. Nightingale defied her family's expectations and pursued her "God-given" talent of nursing, pioneering the modern standards of health care we know today.

Mary Eliza Mahoney - Noted for becoming the first African American licensed nurse, Mary Eliza Mahoney was born to freed slaves in 1845, in Boston. Mahoney began working at the New England Hospital for Women and Children, where she would work for the next 15 years, taking on many roles from janitor to cook, before eventually working as a nurse's aide where she learned an enormous amount about the profession.

In 1878, Mahoney attended one of the first nursing schools in the United States at the New England Hospital where she became the first African American in the U.S. to earn a professional nursing license. Mahoney co-founded the National Association of Colored Graduate Nurses and eventually became the director of the Howard Colored Orphan Asylum for black children in New York City.

Clara Barton - In 1881, At 59 years old, Clara Barton founded the American Red Cross, which she ran for 23 years. Before fouding the organization for which she is perhaps best known to this day, in 1854, Barton was the first woman to be hired as a recording clerk at the U.S. Patent Office in Washington D.C. She was payed the same as her male colleagues but was transferred as a copyist the following year with a lower salary.

Barton quit her job when the Civil War broke out, making it her mission to bring medical supplies to Union soldiers in need and earning her the nickname the "angel of the battlefield."

Margaret Sanger - In 1916, Sanger opened up the first birth control clinic in Brownsville, Brooklyn but was arrested shortly thereafter for distributing birth control information, which was illegal at the time. She spent 30 days in jail, during which time she garnered substantial media attention and support from the public.

In 1929, Sanger formed the National Committee on Federal Legislation for Birth Control to lobby Congress for legislation permitting doctors to prescribe birth control. Her efforts would eventually lead to widespread use of contraceptives in the United States.

Walt Whitman - Famed American poet and journalist Walt Whitman began his career as a nurse after witnessing the injury of his brother, who had suffered a facial wound from a Civil War battle in Virginia. Working as a journalist during the Civil War and visiting war zones throughout the country, Whitman was moved by the sight of the suffering soldiers, leading him to volunteer to work as a nurse in battlefield hospitals.

Whitman would wander hospital camps writing down wounded soldiers' messages to their families, promising to send them. He would go on to work in hospitals in Washington D.C. for the remainder of the war.