Tony,
I believe that the Church had a ruling regarding remarriage to one’s sibling.
quote: “On the 25th of June 1503, she was formally betrothed to the king’s second son, Henry, now prince of Wales, and a papal dispensation for the alliance was obtained.”
Further - “… Catherine gave birth to six children (including two princes), who were all stillborn or died in infancy except Mary, born in 1516, and rumour did not fail to ascribe this series of disasters to the curse pronounced in Deuteronomy on incestuous unions.”
"The act of marriage, which depended for its validity on the decision of the ecclesiastical courts, had, on account of the numerous dissolutions and dispensations granted, not then attained the security since assured to it by the secular law. For obtaining dissolutions of royal marriages the facilities were especially great. "
“In Henry’s case also the irregularity of a union, which is still generally reprobated and forbidden in Christendom, and which it was very doubtful that the pope had the power to legalize, provided a moral justification for a dissolution which in other cases did not exist.”
Note that a papal dispensation was required to allow Henry to marry his dead brother’s wife. My choice of the word ‘annulment’ was incorrect and should have been 'dispensation. To annul the marriage of Henry and Catherine would have meant the Pope had made a mistake in granting the initial dispensation allowing them to marry. Note also that Catherine’s inability to produce a living male heir, prompted many to believe in the words “rumour did not fail to ascribe this series of disasters to the curse pronounced in Deuteronomy on incestuous unions.” Thus many believed that the marriage between Henry and Catherine defied the word of God and was ‘incestuous’ as he married his brother’s wife.
This however, contradicts my memories of the bible, as I believed that a brother had a sense of duty to his deceased brother’s wife and was required to take her as his wife.