Cika wannan jumlar: A farkon Yakin Peninsular (1807<unk>14) Faransa da Spain sun rattaba hannu kan Yarjejeniyar Fontainebleau a watan Oktoba 1807. Wannan ya ba da damar mamayewa da kuma rarraba yankin Fotigal zuwa masarautu uku. Daga baya, sojojin Faransa karkashin jagorancin Janar Junot sun shiga Portugal, wanda ya nemi taimako daga Burtaniya. A watan Yulin 1808 sojojin da Sir Arthur Wellesley, wanda daga baya Duke na Wellington, ya ba da umurni, suka sauka a Portugal kuma suka ci sojojin Faransa a yakin Basra.
Roliça da kuma Vimeiro. Wannan ya tilasta wa Junot yin shawarwari game da Yarjejeniyar Cintra, wanda ya haifar da kwashe sojojin Faransa daga Fotigal. A watan Maris na 1809, Marshal Soult ya jagoranci wani sabon tafiyar Faransa wanda ya ci gaba zuwa kudu zuwa birnin Porto kafin sojojin Portugal da Birtaniya suka kori su kuma suka janye. Bayan wannan koma baya, sojojin Wellesley sun ci gaba zuwa Spain don shiga sojojin Spain 33,000 karkashin Janar Cuesta. A Talavera, da ke kudu maso yammacin Madrid, suka fuskanci kuma suka ci sojojin Faransa 46,000 a ƙarƙashin Shugaba Claude Victor. Bayan yakin Talavera, Wellington ya fahimci cewa sojojin Faransa sun fi shi yawa, wanda ya haifar da yiwuwar cewa za a iya tilasta masa komawa Portugal kuma mai yiwuwa ya kwashe. Ya yanke shawarar ƙarfafa yankin da aka ba da shawarar kwashewa a kusa da Fort na São Julião da Barra a bakin kogin Tagus, kusa da Lisbon.