Oldest companies

So, a mate had a tinkle on the drums last week, and he mentioned that Zildjian (cymbal makers) were the world's oldest company and he said that they've been making instruments for years.
As ever I was skeptical (seeing as it was an american firm), although I wondered what the worlds oldest company was, and where zildjian ranks in all this...

When do you think the earliest company was founded??
1800? 1500? 1100? 718?
578!? :)

http://www.familybusinessmagazine.com/oldworld.html