There were several marriages between D.Pedro and D.Miguel descendants, all of them with major generations gaps
There are some interesting generational gaps between certain royals/nobles (or descendants thereof) who are not all that far apart in age.
Two that pop to mind:
Prince Nicola Pignatelli (1648-1730) and his wife (and agnate) Princess Giovanna (1666-1723). They were half great-granduncle and half great-grandniece. Nicola was the son of Guilio Pignatelli, Prince of Noia via his third wife while Giovanna was his great-great-granddaughter through his first wife.
Guilio → Nicola (1648-1730)
Giulio → Fabrizio → Ettore → Andrea Fabrizio → Giovanna (1666-1723)
The other, when Lennart Bernadotte, Count of Wisborg (formerly Prince of Sweden and Duke of Småland) became a father for the last time the same year his first great-grandchild was born, I think.
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