The Jewels of Kinfairlie is a trilogy of medieval Scottish romances and a short story. The three books in this series each feature one the first three siblings who are the grandchildren of Merlyn and Ysabella, introduced in The Rogue. The Ballad of Rosamunde is a short story and the story of the baby found by Gawain in The Scoundrel.
This series is also available in Audio, narrated by Saskia Maarleveld.
There are Ravensmuir family trees available for free download on the Delacroix site. Each book cover is linked to the landing page for that book on the Delacroix site.

The Jewels of Kinfairlie series is also available in a hard cover collectors edition, including all four stories in the series and family trees.