Davout has marched out of Pamplona with only two divisions of his corps and was surprised to find a Spanish Corps arriving at Longrono from Calahorra on the evening of July 3rd. Messages were urgently sent back from both camps for reinforcements. For the Spanish, General Castanos travels through the night to arrive with some more artillery on the battlefield. Both of the small armies deployed for battle, preparing to fight the next day.

Strategic Battlefield Map

The battlefield is a couple miles east of Longrono with the French deployed east of the village of Viana. Both generals put their cavalry on the western flanks, looking perhaps to limit their opponent's ability to control the roads to the west (Belarado and Pancorbo).

The French advance a short ways before commencing to deploy their infantry division into lines, each brigade having attached artillery, and daring the Spanish to come onto them. Davout knows that he has reinforcements coming and suspects that the Spanish do not. He will bide his time. General Castanos is in the mood to fight though and begins to advance his right to make a classic right oblique attack. He would order his leftmost division to deploy into squares, in anticipation of French winning the cavalry battle. 

The Spanish columns are easily stalled by the fire from the French infantry and artillery.

After several hours, the French cavalry achieve a significant success. First, they rout Spanish lancers and then go on to send Spanish infantry fleeing to the rear. Failing to recall they would slam into one more Spanish infantry brigade that would, once more, fail to form squares.

 The Spanish militia cavalry on the far left could only stand and watch the ruin of Cuesta's center, for if they went forward, French dragoons would charge down upon them. The infantry brigade though, from the Sanguesa division, would stand firm and send the French Hussars bouncing back.

The Spanish are taking losses but they continue to press. The French cavalry would be subjected to massed artillery of the Spanish for hours as it sought to regroup and would eventually be routed to the rear.

The Spanish right begins to make headway. Once they get into musket range, they could begin to inflict steady losses to the French but they cannot long withstand the close range artillery fire.

Within hours, Castanos' army is a spent force, exhausted. The left has finally begun to advance but the center and right have all but ceased to be a fighting force. Worse, the French have been reinforced by a large mixed division, with two brigades of infantry and two of cavalry, nearly doubling Davout's force size.

Davout's infantry division drops from Fresh to worn. His cavalry is weakened. For the Spanish, two infantry divisions are worn and all other divisions are weakened. Even Castanos headquarters is weakened by the fight. The Spanish withdraw toward Calahorra after fighting for seven and a half hours, and look to see how much further they will suffer in pursuit.