Shortly after the birth in 1554 of Sebastian, the last of the dynasty of Avis, a doctor in attendance named Maldonado cast his horoscope. Among other things, the horoscope predicted that Sebastian would be given to "pleasures" with women, and that his wife would give him many noble and handsome children. Since Sebastian never married and had no children in spite of the fact that producing heirs was one of the primary duties of royalty, Sebastian's failure to do so prompted author Harold B. Johnson to examine Sebastian's life more closely in an attempt to understand why. These researches led...