[13] Henry IV of France, after the surprise of the capture, immediately and quickly built up an army which included a large English force and besieged Amiens on 13 May.

[15][16] As a result of the victory, Henry was in a strong position to enact the Edict of Nantes and to negotiate the peace of Vervins which was signed with Spain the following spring.

[20] However, only in 1595 was war officially declared between the two countries by the new French king, Henry IV, who had converted to Catholicism and been received into Paris the year before to be crowned with popular support.

[4] From then on, the civil war began to turn against the hardliners of the Spanish-supported Catholic League, including two major royal French victories over the Spanish at Fontaine-Française and Ham, in 1595.

In 1597, Hernando Tello Portocarrero, the Spanish governor of the town of Doullens, proposed a plan to Archduke Albert, sovereign of the Habsburg Netherlands, to take the capital of Picardy, Amiens, by surprise.

[21][22] The Archduke agreed and saw the acquisition of Amiens as compensation for the recent defeat at Turnhout in Brabant by Anglo-Dutch forces led by Maurice of Nassau earlier in the year.

[27][28] However, money was short in the French war chest and much dissent was caused amongst Henry's old Huguenot allies, many of whom refused to join and wanted concessions now that he had become a Catholic.

[24] In a form of high diplomacy, Henry gave the Huguenots hopes of substantial rights and he made sure to stick to that guarantee once the siege was over.

[23] Four days later, François d'Espinay de Saint-Luc, the grand master of artillery, was killed by an arquebus and Henry mourned him greatly.

On 10 September, Caraffa was informed that two Spanish relief armies were under way: one under Archduke Albert and the other under Peter Ernst I von Mansfeld-Vorderort consisting of over 25,000 men which included veteran Tercios.

[27] Charles, Duke of Mayenne, was able to convince Henry IV and Biron not to confront the huge relief army, but to remain in the entrenchments knowing they were outnumbered nearly two-to-one if in open battle.

[34] After passing the abbey of Bettancourt, Albert attempted to throw a bridge over the river Somme below the village of Longpre but due to poor weather and rising waters he resolved to find another way.

[32] Another attack was planned for the next day, but on observing the French and English force in the strengthened trenches, Albert decided not to risk further heavy losses.

[28] The king immediately followed with the greater part of his army so that the Spaniards were constantly harassed but the Archduke avoided battle and withdrew quickly under the cover of darkness.

[5] As the surrendered troops marched past they pulled with them hundreds of carts loaded with dead and wounded while the Spanish officers saluted Henry.

[11] Amiens was then strongly garrisoned and given much stronger defences under the supervision of the French mathematician and military engineer Jean Errard.

[25] The siege had strategic consequences: Albert's concentration on Amiens meant that the Spanish forces guarding the border with the Dutch Republic were left on their own, enabling Maurice of Orange to capture several cities in his celebrated campaign of 1597.

While peace negotiations were being held with Philip, towns threw out the last League stalwarts and any supporting Spanish garrisons, who offered minimal resistance.

[4][19] In conjunction with Spanish financial distress, its insolvency caused by the capture of Cadiz, two costly failed armadas (in 1596 and 1597) against England, coupled with the increasingly unsuccessful war against the Dutch, meant that Spain had too much to deal with.

[9]: 266 [38] Vervins was the final defeat of Philip II, and a sign of the long downfall of Habsburg Spain and the gradual rise in the European hegemony of France during the ensuing Grand Siècle.