John Johnson, Esq. - Wives for John Johnson Esq?

Is there more than one wife?

The will of John Johnson Esq lists his children as Sarah, Godschall, John and Julia.

FamilySearch entries for John and Julia have a different mother to Sarah and Godschall.

The Wikipedia entry for the son John ,with the same birth and death dates as the FamilySearch entry for John suggest a different mother again.