title: How to merge two git repositories with different root folder keeping history
body: <p>I'd like to merge two Git repositories:</p>
  <ol>
  <li><code>Repo1: Root/A/Subfolders</code></li>
  <li>with <code>Repo2: Root/Subfolders</code></li>
  </ol>
  <p>Historically Repo2 originated from Repo1 but during creation has been &quot;shallowed&quot; by the folder A. Now I need to merge Repo2 back to Repo1 keeping history, but as far as I know cannot simply add Repo2 as remote in Repo1, due to the slightly different structure. Only the history of Repo1 is crucial to me, Repo2 is much &quot;younger&quot;.</p>
  <p>Is there an easy solution to the problem?</p>