Ryan Giggs in the Premier League
Stoke City Britannia
The longest serving manager in the English premier league is Sir Alex Ferguson. Next is Arsene Wenger. But the longest serving ENGLISH manager in the premier league is Steve Bruce, who ranks third overall. ref. http://en.wikipedia.org/wiki/List_of_English_Football_League_managers_by_date_of_appointment
Because it's seen as the most prestigious league in the world. It is also officially Barclay's Premier League or the English Premier League and is just shortened to plain premier league.
The Premier League used to be called the Football League First Division but in 1992 the teams in the Premier League branched off from this championship. There is really no reason that the Premier League is called the Premier League other than Premier meaning good and needing to incorporate "League" in the name. Note that at the moment the Premier League is called the Barclays Premier League because of sponsorship (Barclays being the bank.)