Status Updates From The Twelfth House

why does this book suddenly bring of the phrases ”from the river to the sea“ and ”the lost tribe“ over and over again in a chapter set in 1394 (pre-colonisation) among indigenous Carribeans?? what am I missing here, or is it genuinely a coincidence? i‘m so confused

17

Dual timeline. William and Alden , friends who are separate in believing in slavery. William has slaves. THe birth of a bastard daughter product of rape between WILLIAM and the slave names Agnes.