If your horse is registerd, you will be able to find him in the stud book of the apropriate society or on the apropriate registry.
If you don't know who the sire and dam are, then it does not look hopeful. Your best course of action might be to ask previous owners who bred him and ask them.
thats ok!! i just wondered!! there is nothingg in his passport!! apart from his first owner so if i was desperate to find out in time i can always try and contact him