Following a recent discussion on the Spanish forums about the Spanish line of succession, it occurred to me to ask here what is meant by a "dynastic marriage" today.
Many people often equate dynastic marriages to "equal marriages", i.e., marriages between members of two sovereign (or formerly sovereign) families. However, I don't think that is correct. In my humble opinion, "dynastic marriage" simply implies a marriage whose descendants retain dynastic rights, which, for sovereign families, means primarily a place in the line of succession to the throne, but may also mean in some cases a royal title and style, or other dynastic prerogatives.
I would say then that any marriage of a person in the line of succession that is consented to (in whatever form the law or the constitution of the realm prescribes) is now "dynastic" in the sense that I alluded to in countries like Belgium, Denmark, the Netherlands, Norway, Sweden, and the United Kingdom (in the latter case, only for the first six persons in line). Similarly, any marriage of a person in the line of succession that is not prohibited under the terms of Art. 57(4) of the Spanish constitution is now a "dynastic marriage" in Spain. It is irrelevant whether the person whom the royal is marrying is also a royal himself/herself, an aristocrat, or a commoner.
What do you think?