Unfuwain, one of Britain's leading stallions, died Wednesday at the age of 17 at the Shadwell Estate Company's Nunnery Stud in Norfolk, England. The cause of death was said to be a neurological condition Unfuwain developed suddenly over the weekend. Trained by Dick Hern to victory in the Princess of Wales's Stakes and the Jockey Club Stakes, both 1 1/2-mile Group 2 contests run at Newmarket, Unfuwain was the son of two of the Thoroughbred world's best producers, Northern Dancer and Height of Fashion, thus making him a half-brother to both Nashwan and Nayef. At stud he sired two very good fillies in Petrushka, the winner of three Group 1 races, and Lailani, a two-time Group 1 winner in Europe as well as the winner of the Grade 1 Flower Bowl Invitational at Belmont Park.