Mesca Amuntic

 was the mother of one of the sons which was involved in a succession crisis. One of the other mothers, Wembik, poisoned her on the orders of the human tracer Zara. The Fifth Doctor concocted an anti-venom, and she recovered. Before the crisis she was set to be married to Thetris, but after negotiations by the Fifth Doctor's companion Amy, she was to marry Wembik with Mesca's son becoming the King so they could both be mother to the king. She was trapped inside the castle on Safeplace, which was a segment to the Key to Time, once Zara turned it back into its original form, and released once Amy briefly turned the segment back into a castle, allowing her to escape before the segment was turned back into a crystal. (AUDIO: The Judgement of Isskar)