Rubuta ci gaba don wannan sakin layi - Haɗin kan Biritaniya a cikin Yaƙin Peninsular ya kasance farkon yaƙin neman zaɓe na dogon lokaci a Turai don haɓaka ƙarfin soja na Burtaniya a ƙasa da kuma 'yantar da yankin Iberian daga Faransanci. A watan Agusta 1808, sojojin Burtaniya 15,000 - gami da Sojojin Jamusawa na Sarki - sun sauka a Portugal a karkashin jagorancin Laftanar Janar Sir Arthur Wellesley, wanda ya kori rundunar sojojin Henri François Delaborde ta 4,000 a Roliça
a ranar 17 ga watan Agusta kuma ya murkushe babbar rundunar Junot ta mutane 14,000 a Vimeiro. An maye gurbin Wellesley da farko da Sir Harry Burrard sannan kuma Sir Hew Dalrymple. Dalrymple ya ba Junot izinin ƙaura daga Portugal ta Royal Navy a cikin Yarjejeniyar Sintra mai rikitarwa a watan Agusta. A farkon Oktoba 1808, bayan abin kunya a Biritaniya game da Yarjejeniyar Sintra da kuma janye janar Dalrymple, Burrard, da Wellesley, Sir John Moore ya jagoranci rundunar sojojin Birtaniya 30,000 a Portugal. Bugu da ƙari, Sir David Baird, a matsayin kwamandan wani tafiye-tafiye na ƙarfafawa daga Falmouth wanda ya kunshi jigilar 150 da ke dauke da mutane 12,000 zuwa 13,000, wanda HMS "Louie", HMS "Amelia" da HMS "Champion", suka shiga Corunna Harbour a ranar 13 ga Oktoba. Matsalolin kayan aiki da na gudanarwa sun hana duk wani mummunan harin na Birtaniya.