[Grammar] Is/was supposed to

[LeonieSto]

Hi everyone,

Is it possible to say "This incident is supposed to have a world-changing effect on medicine" when one is talking about the past? Like the incident already happened about 200 years ago but it had a significant effect on medicine.
Or do I have to say that it was supposed to have.. ?

Thank you

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[The Maltese Falcon]

Because it is in the past tense you would have tosay "This incident was suppose to have had a world-chaning effect on medicine" Note the 'have had'.
However if it is something that has certainly happened, you could simply use the past perfect saying "This incident had a world-chaning effect on medicine"

I hope this helps!
TMF