From wikipedia:
Highlander Designs went bankrupt and was bought by Brittannia Game Designs Ltd. (BGD), a company based in England and directed by Steve Turner. The fourth edition of C&S, called "The Rebirth" was born a few months later. The result was the return of some medieval references and some gameplay mechanics (such as "bash" or "Targeting" for spells) adding this degree of realism that was lacking in the previous edition. Moreover, many additions to the rules (such as "Laws of Magick") brought novelty to the game.
The core rules had several extensions, including the "Knights Companion", "Armourers Companion," "Dwarves Companion" and "Elves Companion". BGD also wanted to develop their own world "Marakush". Despite the interest of a certain segment of the population for a type of game that is realistic and that C&S has been an example of, sales of C&S4 were not sufficient to ensure the continuity of the game and stopped producing.