Pedro I of Brazil, who has abdicated in favour of his son in order
to return to Portugal to help his daughter Maria II, takes Oporto
with the aid of France and Britain. The forces of his rival brother
Dom Miguel are defeated.
Citation:
Editors. "Dom Pedro takes Oporto with French and British aid".
The Literary Encyclopedia. First published 30 December 2011
[http://www.litencyc.com/php/stopics.php?rec=true&UID=17973, accessed 23 May 2013.]