Short answers, pulled from the story.
Phoebe was discovered by William Henry Pickering on the 18th of March 1899. He identified it from photographic plates taken by DeLisle Stewart starting on the 16th of August 1898 at the Boyden Station of the Carmen Alto Observatory near Arequipa, Peru. It was the first natural satellite discovered photographically.
Phoebe follows a retrograde orbit, meaning it travels in the opposite direction to Saturn's own orbital motion. This places it in Saturn's Norse group of irregular satellites, which are thought to be captured bodies rather than moons that formed alongside the planet.
Scientists now widely believe Phoebe is a captured centaur from the Kuiper belt. Spectroscopic data from the James Webb Space Telescope and Cassini's VIMS instrument show water ice and carbon dioxide on its surface, and its overall spectrum closely resembles that of Kuiper belt objects. It may have formed within three million years after the origin of the Solar System.
The Phoebe ring is a vast but nearly invisible ring of Saturn tilted 27 degrees from the planet's equatorial plane, extending from at least 128 to 207 times Saturn's radius. It was discovered using NASA's infrared Spitzer Space Telescope. Particles in the ring are thought to originate from micrometeoroid impacts on Phoebe and share its retrograde orbit.
Cassini passed just 2,068 km from Phoebe's surface on the 11th of June 2004. The flyby was Cassini's first encounter upon entering the Saturn system, and the spacecraft's trajectory and arrival time were deliberately chosen to make it possible. The encounter allowed scientists to determine Phoebe's mass with an uncertainty of only 1 in 500.
In 2005, the International Astronomical Union officially named 24 craters on Phoebe after characters from the Greek legend of Jason and the Argonauts. The largest crater, Jason, is roughly 100 km in diameter. The IAU chose the Argonaut theme because it resonated with the Cassini-Huygens mission's exploration of the Saturn system.