From the 1860's onwards: Accross the Atlantic!
The Civil War was raging in the United States and the soldiers needed feeding. At the time there were no canneries or very few of them on the spot. Thanks to the sterilisation process, canned sardines kept very well and could be transported easily.
This was the beginning of the export trade.
With the Western rush following the war, the United States offered unlimited opportunities. The demand for canned sardines increased and our tins of sardines in olive oil became very popular on the other side of the Atlantic.