Ambrogio Spinola Doria, 1st Marquess of Los Balbases and 1st Duke of Sesto (1569 – 25 September 1630) was an Italian condottiero and nobleman of the Republic of Genoa, who served as a Spanish general and won a number of important battles.

He is often called "Ambrosio" by Spanish-speaking people and is considered one of the greatest military commanders of his time and in the history of the Spanish army.

Several of the younger brothers of Ambrogio Spinola sought their fortune in Spain, and one of them, Federico, distinguished himself greatly as a soldier in the Army of Flanders.

He was not successful, and having lost a lawsuit into which he had entered to enforce a right of pre-emption of a palace belonging to the Salerno family which the Doria wished to purchase, he decided to withdraw from the city and advance the fortunes of his house by serving the Spanish monarchy in Flanders.

His experience as a soldier did not begin until, as General, and at the age of thirty-four, he undertook to continue the Siege of Ostend on 29 September 1603.

The governor of Flanders Archduke Albert and the Infanta Clara Eugenia, daughter of Philip II, who had set their hearts on taking Ostend, were delighted at Spinola's success, and it won him a high reputation among the soldiers of the time.

At this period, the wars of the Low Countries consisted almost entirely of sieges, and Spinola made himself famous by the number of places he took in spite of the efforts of Maurice of Nassau to defend them, including heavily fortified Groenlo.

He was received with much outward honour, and entrusted with a very secret mission to secure the government of Flanders in case of the death of the Archduke or his wife.

However, he could not obtain the grandeeship which he desired and was compelled to pledge his entire fortune as security for the expenses of the war before the bankers would advance funds to the Spanish government.

After its surrender, he gave safe passage to its leaders and soldiers, who were allowed to leave the city with their banners and arms, an extraordinary and magnanimous gesture that made Spinola famous throughout Europe.

Spinola could not prevent Frederick Henry of Nassau from taking Groll (or Groenlo) in 1627, a good set-off for Breda.

In Italy, he was pursued by the enmity of the Conde-Duque of Olivares, who had been, curiously enough, born in Rome in 1587, where his father, don Enrique de Guzmán y Ribera, a cadet child from one of Spain's oldest noble families, was the Spanish ambassador.

"[3] The title of "Marquess of Los Balbases", still borne by his representatives in Spain, was all that his family received for the vast fortune they spent in the service of Philip III and IV.