Short answers, pulled from the story.
Robert E. Howard is credited with originating sword and sorcery through his early 1930s works, particularly the Conan the Barbarian stories published in Weird Tales. Isaac Asimov stated that "The contemporary Sword-and-Sorcery tale owes its existence to the imagination of Robert Howard and his invention of the Conan stories." Howard's 1929 story "The Shadow Kingdom" is often regarded as the first true sword and sorcery tale.
Fritz Leiber coined the term sword and sorcery in the 6th of April 1961 issue of the fantasy fanzine Ancalagon, responding to a request from British author Michael Moorcock in the fanzine Amra. Leiber described it as "a good popular catchphrase for the field." A 1953 review headline had used the phrase earlier, but Leiber's usage in 1961 established it as the genre's name.
Sword and sorcery focuses on personal battles and individual survival rather than world-threatening conflicts that define high fantasy. The protagonist is typically an antihero pursuing personal or mercenary aims, magic comes at a substantial cost and is usually wielded by villains, and the moral framework is grayer. High fantasy is more concerned with the struggle between absolute good and evil on a civilizational scale.
Robert E. Howard's 1929 Weird Tales story "The Shadow Kingdom," featuring Kull of Atlantis, is widely regarded as the first true sword and sorcery tale. Howard's Conan the Barbarian stories followed from 1932, with 17 published in Weird Tales. C. L. Moore's Jirel of Joiry stories in Weird Tales introduced the genre's first female sword and sorcery hero.
Women were both important early creators and subjects of debate within sword and sorcery. Robert E. Howard wrote strong female characters including Dark Agnes de Chastillon, first appearing around 1932-34, and Valeria of the Red Brotherhood in 1936. C. L. Moore, Leigh Brackett, and Andre Norton were foundational authors. Marion Zimmer Bradley's Sword and Sorceress anthology series from 1984 and Jessica Amanda Salmonson's World Fantasy Award-winning Amazons anthology from 1979 challenged the genre's masculine bias.
Lancer Books' paperback reissues of Robert E. Howard's Conan stories in the 1960s, featuring cover illustrations by Frank Frazetta, became surprise bestsellers and sold millions of copies to a largely young readership. This commercial success prompted other publishers to release their own books in Howard's style, triggering a broad expansion of the genre that brought in writers like Michael Moorcock, Fritz Leiber, and later Andre Norton, Tanith Lee, and Karl Edward Wagner.