Short answers, pulled from the story.
The ancient name for the natural magnet known as lodestone is magnētis lithos, or the Magnesian stone. This mineral is a form of magnetite and was the first evidence of magnetism that humans ever encountered.
William Gilbert published his groundbreaking work De Magnete, Magneticisque Corporibus, et de Magno Magnete Tellure in 1600. This publication concluded that the Earth itself was a giant magnet and moved the study of magnetism from philosophical speculation to empirical observation.
Hans Christian Ørsted discovered the connection between electricity and magnetism in 1819 when a compass needle twitched near a wire. This landmark experiment, now known as Ørsted's Experiment, showed that an electric current could create a magnetic field.
When a ferromagnetic substance is heated beyond its Curie temperature, the molecules are agitated to the point that the magnetic domains lose their organization. The magnetic properties they cause cease to exist until the material is cooled and the domain alignment structure spontaneously returns.
Magnetic monopoles have never been observed despite systematic searches since Paul Dirac predicted them in 1931. A monopole would be a new and fundamentally different kind of magnetic object acting as an isolated north pole not attached to a south pole.