The response is given in XML and all you require is:
*Api Key (Generate from my profile
*64bit ID to look up (example:76561197977933359)
Example request: https://steamid.eu/api/request.php?api=test&player=76561197977933359
Example Error Response:
1) Player / ID not found
2) ID Incorrect / too long
3) Api Key not recognised
4) You are over the API threshold contact the site to get more "credits"
5) No ID
6) No API key
If there is no name history, it will throw an error previous_name->error->"None found"