Hello

Indeed Hohenzollern-Sigmaringen were a 'small' sovereign family...in fact when they were married, this family held only sovereign status because Stephanie's father had given up his Principality to his cousin the King of Prussia...
When King Pedro wanted to marry, Europe experienced a great deficit of marrying princesses...
He wanted to marry Pss Charlotte of Belgium, and King Leopold wanted sincerely this to happen, but she was inlove with the future Emperor of Mexico...Leopold tried his best to see her married to the Portuguese King, but she had her own opinion...
He turned to Britain's Princesses, but Queen Victoria, though she had great estime towards her Portuguese cousins, felt the religious differencies were an intransponible wall...Her uncle Leopold reproched her for this...
In Spain there were some Infantas available...but Pedro didn't want them...
Then Prince Albert of Great Britain suggested Stephanie: she was pretty, had the same age as Pedro, and was a Catholic with connections to Protestant families (Baden, Prussia)...
While studying her ancestors, Pedro did not like the Murats and Beauharnais linkeage...Prince Albert remembered him that his grand-father (Emperor-King Pedro I-IV) had married a Beauharnais

...
Than he send his emissary (Lavradio)...and after some arrangements...the marriage was done...
The King of Prussia made a little 'chantage' before he gave his permission: the exiled King Dom Miguel I (whom Pedro appreciated in secret) lived in bad conditions...not dignified enough for a man of his status...King Pedro gave support to his mother' s uncle...Miguel refered to Pedro as 'o meu anjo da guarda' (my guardian angel)...