The War of the Spanish Succession ended in 1714 following the compromise Peace of Utrecht which kept the French candidate Philip V on the throne, but forced him to give up many of his overseas possessions.

However, Spain wished to reclaim lost territories in Italy and in 1718 invaded Sicily and Sardinia, triggering a fresh war with Austria in the belief that none of the other great powers would intervene.

In turn Spain tried to knock both out of the war by launching an invasion to support a planned Jacobite uprising in Britain while also engaging in the Cellamare conspiracy, a plot to overthrow the French government.

Although there was some scepticism whether France would really attack their recent allies, in April 1719 French forces began crossing the border, and they were joined by Berwick who departed Bordeaux on 11 May.

[5] The French invested San Sebastian on 30 June, and began positioning batteries along the River Urumea where Berwick considered the city's walls were most vulnerable.

As was the convention at the time, the Spanish commander Alexandro de la Motte requested a parley and his garrison were allowed to retreat into the citadel, leaving the remainder of the city to French control.

[8] On 11 August a detachment of 750 French infantry, escorted by the British Royal Navy, launched a successful attack on a port town of Santoña along the coast beyond Bilbao doing more damage to Spanish naval resources.

[12] Berwick also received similar messages from Catalan leaders, who had during the earlier War of the Spanish Succession supported the rival Austrian candidate Charles and were still resentful of the loss of much of their independence following the Fall of Barcelona in 1714.