past and past perfect tense

1)He had served in the army for ten years;then he retired and married.His children were now at school.

2)He served in the army for ten years;then retired and married. His children are now at school.

Hello,
why do we change had served to served in the second sentence?

Hi,

It would be better to say: He had served in the army for ten years before he retired and married Using ‘had served’ in the first sentence doesn’t automatically link with the next sentence unless you use the conjunction ‘before’, which I have suggsested.

Alan