was/were do do something
'Was/were to do something'
Longman define this phrase as:
Used when talking about a time in the past to say what happened later. Example:
this discovery was to have a major effect on the treatment of heart disease.
I don't thoroughly.comprehend it.
I know the meaning of present tense (is/are to do sth) and the conditional one (if sb was/were to sth), but the simple past form of it, is a kind of ambiguous. Does it mean "unfulfilled intention"?
P.s.
Sorry about the topic sentences, it is a typo.