Whalen, Brett Edward <br/><br/>
The Two Powers: The Papacy, the Empire, and the Struggle for Sovereignty in the Thirteenth Century 

 -  Walter de Gruyter  Walter de Gruyter  2019 
<br/><br/><label>ISBN: </label>9780812296129 
<br/><br/><label>Source: </label>EBOOK 
<br/><br/><label>Subjects--Topical Terms: </label><br/>History