Buenos Aires was in 1838 blockaded by a French fleet; but Rosas stood firm.
Not having sufficient materiel for two sieges, he laid siege to San Sebastian only, and blockaded Pampeluna.
The others were blockaded in Cadiz.
Here he was besieged by Don Frederick of Toledo, Alva's natural son, who blockaded all approach to the town.
By the end of May the city was blockaded by land and sea, and in July the bombardment began.