Is there a way to get airline prices from the past?

I traveled from Frankfurt to Japan in July for an office work. However, as my employer is based in Vienna, I always need to provide some price comparison (in form of a screenshot) for comparable flights from Vienna to the final destination. However, I can't find the screenshot anymore and I am desperately searching for a way to 'recover' prices I would have paid for this flight originally in order to get my flights reimbursed. Is there any way or service which could provide me previous date flights prices?