Short answers, pulled from the story.
In 1991, a court ruling declared that taking even a single second of a sound recording without permission was theft. This decision emerged from a lawsuit between the songwriter Gilbert O'Sullivan and the rapper Biz Markie. The court forced Warner Bros. Records to recall the entire album and remove the track.
The term sampling was coined in 1979 by Kim Ryrie and Peter Vogel. They were the creators of the Fairlight CMI, a synthesizer that could record and play back short sounds. Vogel discovered he could imitate a piano by playing a recording back at different pitches.
James Brown is sampled in more than 3000 tracks, more than any other artist. His drum break from the 1969 track Funky Drummer was used extensively by hip-hop producers. Loleatta Holloway is the most sampled female singer.
In 1996, DJ Shadow released Endtroducing, the first album created entirely from samples. He used an MPC60 to construct a complete work without any original recordings. This achievement proved that an entire album could be built from the fragments of other people's music.
The United States Court of Appeals for the Sixth Circuit ruled that all samples, no matter how short, required a license. The case involved the hip-hop group N.W.A. and their use of a two-second sample of a Funkadelic song in the 1990 track 100 Miles and Runnin'. A judge wrote that producers must get a license or not sample.
In 2019, the European Court of Justice ruled that the producers Moses Pelham and Martin Haas had illegally sampled a drum sequence from the 1977 Kraftwerk track Metal on Metal. The court ruled that permission was required for recognizable samples while modified, unrecognizable samples could still be used without authorization.