public sealed class HistoricalVersionDescription 

{
  // Must be called within QueuedTask.Run
  HistoricalVersion CreateHistoricalVersion(Geodatabase geodatabase, string versionName)
  {
    using (VersionManager versionManager = geodatabase.GetVersionManager())
    {
      HistoricalVersionDescription historicalVersionDescription =
        new HistoricalVersionDescription(versionName, DateTime.Now);
      HistoricalVersion historicalVersion =
        versionManager.CreateHistoricalVersion(historicalVersionDescription);

      return historicalVersion;
    }
  }
}