Without any information, can't do much. People have been manufacturing bikes under the name Royce Union since the early 1900s in various countries. Name was bought by huffy in the late 90s. Kinda disappeared after that. Since you said BMX I'm going to guess somewhere from 95-97 for yours.
I have ~'80 RU Motomag copycat...so, they were in the BMX game for quite a while. So, as Matti mentioned, pics and serial will be needed to narrow it down.