Bartholomew is Lia's cat. He was a stray and she got him when Sphinx, who'd been taking care of him outside, didn't want him to be out in the winter. Lia fell in love with that gentle silver boy at once and calls him a soul companion.
Bartholomew moved from New York to England when Lia moved in with David at Beak's End. He is very pleased with his 33 rooms and co-exists peacefully with Grace and Dmitri.