Infante D.Afonso de Portugal, cardinal (1509-1540), archbishop of Évora and Lisbon.
His younger brother, Cardinal D.Henrique, was the last king of Portugal of the Aviz dynasty (1512-1580).
Felipe V of Spain's youngest son, Infante D.Luis was elevated to cardinal but renounced a religious career and contracted a morganatic marriage.
Some Habsburg archdukes were cardinals:
Albert of Habsburg, Maximilian II's son, was a cardinal and vice-roy of Portugal.
Andreas, Margrave of Burgau
And there is of course Duke Amedeo VIII of Savou who abdicated and was elected Anti-Pope (jumping the cardinal style)
One of his descendants was cardinal Maurizio di Savoia (1593-1657)
: Can anyone provide a list of double princes,
: in European royal history? By which I mean:
: those royals who got elevated to the Sacred
: College. Cardinals, as I understand, are
: "princes of the Church" -- ranking
: directly behind only the Pope, the supreme
: pontiff. As such, they are the Catholic
: religion's version of royalty.
: The only real prince I personally can think
: of offhand, who became a prince of the
: Church, however, is Henry Stuart -- younger
: son of James the Pretender (whose father,
: King James VII/II, got deposed from the
: British throne during the Glorious
: Any other examples? I'm sure there must be
: lots -- just as there have been numerous
: royal women who took up religious life.