Arcalian Chapter

The Arcalian Chapter (occasionally known as Arcal) was the second-most important(after the Prydonian Chapter) of the six Time Lord Chapters or Colleges. Arcalians wore green and brown robes. (DW: The Deadly Assassin)

The Arcalian Chapter were (most likely) a part of the Arcalian Council for Temporal Research. (PDA: Spiral Scratch)