was or were

Hello everyone, I have come across a confounded sentence, which is:

[There was a thousand of people at the football match]

I want to clarify why [was] is used here in lieu of [were] as [a thousand of people] means [1000 people], which, in turn, represents many (more than one) guys.

Or I should focus on [a thousand]? Hence I should use [was] in front of it?

Thanks