Terrynate

Terrynate was a Time Lord who served as Castellan on Gallifrey. When the Third Doctor sent a distress call home using the Telepathic circuits of his TARDIS after preventing a war between Earth and Draconia, the distress call was received and actioned on the orders of Castellan Terrynate. The message was eventually stored in the Panopticon Archives. (PROSE: The Time Lord Letters)

Behind the scenes
Terrynate was mentioned in the The Time Lord Letters as part of the document "Telepathic Directions". It provided the exact verbiage of the telepathic message sent by the Third Doctor in the closing scene of the television serial Frontier in Space and offered insight into what happened directly after the message was received on Gallifrey.

His name is reminiscent of Terry Nation, who wrote Planet of the Daleks, the very story which the telepathic message leads into.