Since 1562 France had been in the grip of the French Wars of Religion, in which Spain had regularly intervened in favour of the Catholic League of France. King Henry IV of France had been fighting for the Protestant cause, but in 1594 had converted to Catholicism in Paris on March 22, 1593. The example of Paris was followed by other towns and cities with several chiefs of the League coming over to the king. Henry now directed his chief attention to the fortified towns of Picardy and Champagne from their contiguity to the Spanish Netherlands. From there he received the forced or voluntary submission of the most considerable and at last began to think seriously of his engagements to Elizabeth I of England. Marshal Jean d'Aumont was sent into Brittany to join the English army under John Norreys which had already been fighting there. Several towns enlightened by the presence of d'Aumont with a large body of troops voluntarily declared for the king. The castle of the town of Morlaix was the key to the area which the Catholic Leaguers and Spanish troops held.
Siege
A combined force of Leaguers and Spaniards under the Duke of Mercoeur and Juan d'Aguila respectively decided to come to Morlaix's relief. D'Aumont had already joined the English under Norreys - Elizabeth had demanded beforehand that Morlaix should be granted to the English as a place of retreat. D'Aumont however decided to evade it by a condition that Catholics alone should be admitted. D'Aumont learned that his position and of the Leagues made a looming battle inevitable. Mercour sent a force of Leaguers to Morlaix to make forced marches, and made at least ten leagues in a day hoping to join up with a Spanish force under Juan Del Aguila. Norreys with his force however moved down the coast to block their path so that they wouldn't link up with the Spanish. His approach unnerved Mercour who immediately withdrew from the area to fortified positions not far from Morlaix. Norreys sent 700 English troops to demonstrate before Mercour and hastened him to abandon his advantageous positions. Aguila marched his troops and were close to linking up with Mercour's force but their relief column ran into segments of the detached English. Aguila thought he was up against a much larger force - the Spaniards believed that they totalled 6,000 men but didn't realise that the English was a mere detachment. Aguila fearing being overwhelmed then decided to withdraw his men to Blavet on September 17, which meant that Mercour could not relieve the castle of Morlaix. Tensions reached boiling point soon after with Aguila and Mercour both blaming each other for the failure. Soon matters of the garrison turned for the worse when they spotted an English fleet under Sir Martin Frobisher carrying the siege train of heavy guns for Norreys. On seeing the English ships with their guns run out and on hearing the news of that relief force was not forthcoming from either Mercour or Aguila, the garrison surrendered.
Aftermath
The garrison marched out and the English and French force entered in triumph. The English force under Norreys had dispersed two larger forces; one League and one Spanish and placed them both on the defensive and ultimately forced their retreat. D'Aumont gave high praise to Norreys and allowed him to enter the town first satisfying Elizabeth's order. As a result of the capture many more towns soon joined the King's side. Soon after Quimper and Guingamp were captured by Norreys - but the real prize was Brest; in particular the Spanish fort on the headland commanding the Gironde. The fort was taken in a brutal assault which cost the entire garrison but also nearly a quarter of the besieging force which included Martin Frobisher and denied the Spanish a major base there. English troops left France in February the following year and Elizabeth was able to redeploy her troops back to the Netherlands.
