Short answers, pulled from the story.
Isadora Duncan was born in 1877 into a world where women's bodies were constrained by tight corsets. She rejected the strict movement vocabulary of classical ballet as ugly and meaningless gymnastics that stifled true expression.
Ruth St. Denis and Ted Shawn founded the Denishawn school. Martha Graham, Doris Humphrey, and Charles Weidman all studied at this institution before developing distinctively American movement styles between 1923 and 1946.
Alvin Ailey formed the Alvin Ailey American Dance Theater in New York in 1958 using blood memories from Texas as inspiration. His most popular work Revelations premiered in 1960 and remains critically acclaimed worldwide.
Hanya Holm introduced Wigman technique to America in 1931 after studying with Mary Wigman. She later opened the New York Wigman School of Dance which became the Hanya Holm Studio in 1936.
Merce Cunningham presented his first New York solo concert with John Cage in 1944 introducing chance procedures to choreography. He set the seeds for postmodern dance with non-linear, non-climactic, and non-psychological abstract work where each element was expressive in itself.