Sentence 1: The Keiskamma River marked the border between the Cape Province and former British Kaffraria , known also then as Queen Adelaide 's Province , until 1847 .
Sentence 2: Until 1847 , the Keiskamma River marked the border between the Cape Province and the former British Kaffraria , which was then known as Queen Adelaide 's province .
Question: Do Sentence 1 and Sentence 2 express the same meaning? Yes or No?