Sophia Caswell Ley was the first matriarch of Beak's End. Together with her husband, Aloysius, she worked with the architect to design the regal Georgian manor. The portal was entirely her concept and design.

Sophia was a beauty born into wealth but she was fiercely independent and rejected all suitors. She stunned everyone when she fell in love with eccentric and quirky scientist, Aloysius Ley, sole heir to the Ley fortune as her husband.

From early on, Sophia's parents knew she was in possession of special powers. She was deeply spiritual but also scientific, and she and Aloysius shared the same passion of bridging science and spirituality. Sophia was the first to travel through time and be aware of living in more than one dimension at the same time. She managed to balance her metaphysical pursuits with running Beak's End. Her greatest joy was Aloysius and her two children, Leander and Amelia.

Sophia's seemingly charmed life was not without tragedy. Like her husband, she felt the presence of unseen enemies who wanted their destruction. Her daughter Amelia's mysterious death at age sixteen devastated her, and the pressure caused her ideal union with Aloysius to fray at the edges.

She and Aloysius had been living apart much of the time when he passed on in 1791, but their spiritual connection never weakened and she longed for the day when she could again be with her twin flame. When her son Leander also dies mysteriously at age forty, her only solace is her granddaughter, Virginia Ley, who she considered one of her soulmates. When Virginia dies at age twelve, Sophia no longer wants to be in this world.