>[![enter image description here][1]][1]


  [1]: https://i.sstatic.net/88YRO.jpg

>1. My calling is that of an arch wizard (picture related)

>2. My name is that of Michael. No god am I, but one who serves.

>3. A Barons title is that of a lord, but he may opt to be referred to as Baron (or Baroness) versus lord. 

>4. My job title is that of Head of Commercial Operations, however most of the team call me the Director. 

In all of these sentences, why they use ***that of*** instead of just saying "A is B", such as "my calling is arch wizard"?