In 1983, a seven-day long Quidditch match against the Holyhead Harpies is considered to be "one of the finest Quidditch games ever seen". The captain of the Harriers, Rudolf Brand, proposed to Harpies'captain Gwendolyn Morgan at the end of the match. She hit him with her Cleansweep Five as a reply (QA7).
The word harrier can mean (1) a persistent attacker, (2) a breed of dog used to hunt hares or (3) a bird of prey (Oxford English Dictionary)
The city of Heidelberg is located on the River Neckar in south-west Germany. According to its Wikipedia entry, it has four rugby league teams, two rugby union teams and a basketball team, but no Quidditch team (Wikipedia).