Two-Column Layout with Spanning Header

I want to create a layout for the following html code.

<div>
   Article Header
</div>

<div>
   <div>
      Article Content
   </div>

   <div>
      The Sidebar
   </div>
</div>

There are two columns, and the article header that contains H1 spans across the columns. I thought about wrapping the article's header and content inside an article tag, but is it okay to have the sidebar inside too? Or is there a better way to do that?