The Ramatis system and its colonies were threatened in 2268 by the USS Sphinx, when all aboard were killed and the starship headed uncontrolled at high warp toward the system. Disaster was averted by the crew of the USS Enterprise. (TOS - Section 31 novel: Cloak)
The USS Enterprise-D visited the Ramatis system in 2365, when they transported the famed negotiator Riva (and his chorus) from his home on Ramatis III to Solais V for peace talks (TNG episode: "Loud as a Whisper")
When Commander Tuvok of the USS Titan investigated the Borg attacks of 2381, he noticed that they had all occurred on the border between the Federation and the Klingon Empire, stretching between the Acamar and Ramatis systems. (ST - Destiny novel: Gods of Night)
- See also: Ramatis Choral Debates.