So, we all know that Philip IV of Spain had one surviving son by his first wife Elisabeth of France, that son being Balthasar Carlos who died in 1646. My query is this if Philip and Elisabeth's second son Francis Ferdinand (b.1634) had survived also, would Felipe have been in as desperate a situation to remarry, or would he simply have pawned Francis off to marry Balthasar Carlos's intended bride?
And if Carlos himself had not died in 1646, what would the dynamics at the Spanish court be like with two surviving songs?