VF page with Custom Controller - error = 'Attachments' is not a valid child relationship name for entity Case

I have a cuastom controller that pulls in a specific record type of case. I'm trying to add a realted list for attachments. I added,

<apex:relatedList list="Attachments" title="Attachments" subject="{!Case1}"/>

but I get the following error when I save the case record, " 'Attachments' is not a valid child relationship name for entity Case "

I can't figure out how to get the related listing of attachments. All of the posts I find talking about this topic are old and do not fix my issue.

Any help would be greatly appreciated!!

Fred