These are names of men. (See: [[rc://en/ta/man/translate/translate-names]])
# the fourth ... the fifth
The word "son" is understood. Also, the numbers are in ordinal form. AT: "the fourth son ... the fifth son" (See: [[rc://en/ta/man/translate/figs-ellipsis]] and [[rc://en/ta/man/translate/translate-ordinal]])