With the backing of liberals from Spain and England, and substantial foreign mercenary contingents (who comprised roughly 80% of the liberal forces), Pedro landed near Porto, which the Miguelist forces abandoned without combat. After fighting the inconclusive Battle of Ponte Ferreira, Miguelite forces besieged Porto, engaging in sporadic skirmishes. Throughout the year, most of the battles of the Civil War concentrated around Porto, whose population had whole-heartedly supported the liberal cause. In June 1833, the liberals, still encircled at Porto, sent out a force commanded by the Duke of Terceira to Algarve, supported by a naval squadron commanded by Charles Napier, using the alias Carlos de Ponza. The Duke of Terceira landed in Faro and marched north through Alentejo to conquer Lisbon on 24 July 1833. Meanwhile, Napier's squadron encountered the absolutist fleet near Cape Saint Vincent and decisively defeated it at the Battle of Cape St. Vincent.