Tuesday, June 09, 2020

Marengo Campaign

About 21st April we started a Marengo Campaign.  See blog report of 28 April for general details.  I have been unable to write much in the way of reports on the campaign because it includes hidden movement & there was much I could not say.   But now the campaign has ended I can prvide a full report on it.
The campaign started with the troops in roughly the same positions as the originals on 14 May 1800a as per Esposito's Atlas of the Napoleonic Wars.  The corps sizes were roughly based on Esposito, but not exactly, to present the players with a bit of uncertainty.

The French main army moved towards Lombardy on 3 routes.  Bonaparte with Lannes, Duhesme, Besieres & Murat down the Great St Bernard, Victor on the Simplon & Moncey on the St Gothard.  The Austrians had forts on the passes.  Corps Haddick was on the St Bernard but retreated before the French.  Fort Bard put up some resistance (as it did historically), but surrendered when Bonaparte's artillery arrived.  It was a similar story on the Simplon & Gothard where Corps Vussosovich withdrew without a fight leaving small garrisons in the forts.

Bonapart advanced to the 5-ways at Vercelli & paused his infantry while he sent out his cavalry to find the Austrians.  On finding that Vukassovich was retreating southwards towards Alessandria, Bonaparte sprang into action.  Vukassovich was trapped between Lannes & Victor.  In the battle of Novara described on the blog a few weeks back Vukassovich fought his way around Victor's left flank.  Only to march straight into the Corps of Duhesme.  He has no choice but to surrender with his 8,000 men on June 2.

Down south in Genoa, Massena & his men were beseiged by General Ott.  Ott attacked twice before finally breaking into the city on May 29.   (The real Massena held out a week longer).

On the Riveria, Suchet advanced to find the Austrians in a position at Ventimiglia too strong to attack.  Both forces then retreated. The Austrians fell back to an even stronger line at Port Maurice.  But Suchet marched north up the Col de Tenda.

Meanwhile the Austrians were concentrating their forces at Alessandria, their main supply base.
Bonaparte's forces now marched most of his force east to take the cities of Milan & Pavia leaving a cavalry screen to cover his own line of communication.  Suchet marched unopposed all the way to Asti. Ott left a garison at Genoa & marched to join Melas at Alessandria.

Victor took Piacanza on June 6.   The real Bonaparte got there 5 days faster, but he didn't pause to capture an entire corps.

Having now cut Melas' line of communication with Vienna, Bonaparte turned back to the west.  Victor & Duhesme marched south of the Po towards Alessandria with part of Murat's cavalry going ahead.  The rest of the French crossed the Po north of Alessandria to a position north of a range of wooded hills running E-W south of the Po & half a day's march north of Alessandria.

Large Austrian cavalry parties had previously been sent east & north of Alessandria, but went back before the French had advanced that far, so returned without finding much to report & Melas remained unsure of where the main French army was.

Suchet had found Austrian cavalry at Asti & turned west to Turin.  There he found the Piedamontese garrison commander was a closet Bonapartist & gave up the city.  With communications restored with Bonaparte, Suchet was ordered to march back east to Asti & on to join Bonaparte.

By June 18 almost all the French & Austrian armies were concentrated around Alessandria.  The Austrians in and to the south of the city, 2 French Corps near Marengo to the east, the main French army west of Valenza (north of Alessandria).

Bonaparte then made a bold move to break the deadlock by leaving Suchet & Moncey as a rearguard, marching east to throw a pontoon bridge over the Bermida between Velenza & Sale & moving the rest of his army toward Marengo to join Victor & Duhesme.  But at the same time, the Austrians finally made a move.  Melas moved almost his entire army north towards Suchet & Moncey while Bonaparte's forces were scattered with 2 corps north of Alessandria & 5 to the east of it.

Alessandria is a walled city on the south bank of the Tanaro with a huge star fortress on the north bank.  When he moved north, Melas left a garrison behind in the city to hold off the French coming through Marengo.

Melas didn't know it, but he had the opportunity to attack Suchet & Moncey's 17,000 men with 60,000 men.  But the French occupied a position in an area of broken wooded ground that ran in a band E-W between the Po & Tanaro Rivers.  Previous wargames had educated Melas that the French infantry's superior skirmish ability made fighting them in rough ground a hard task for the Austrians, wedded as they are to linear tactics.  He also had no idea where Bonaparte actually was as his manouvres were hidden by a range of wooded hills.  Melas deployed his advance guard about the village of Castella Montferato on a ridge just south of Moncey & Suchet & deployed his main force behind them.  On June 21 he sent out his cavalry to find Bonaparte.  The hilly wooded country limited the amount of intel the cavalry could obtain, but while the cavalry reported no French to the west & none to east of Valle San Bartolomeo, it was pushed back down the valley of the road to Valenza by superior numbers of French cavalry.


While Melas had hesitated, Bonaparte had abruptly changed his plan.  His troops to the east about faced & force marched back over the pontoon bridge.  Duhesme followed, leaving Victor's 2nd division to cross the Bermida west of Marengo, move up to the walls of Alessandria & commence a bombardment.  By the morning of the 22nd, Suchet & Moncey were no longer alone.  They were now the right flank of the French army deployed on a 10km front in a concave arc in hilly wooded ground that substantially hid them from the Austrians.

Like the real thing, the campaign has lead to a potentially decisive battle near Alessandria. This time to the north of it rather than to the west at Marengo.  Both sides have most their available forces near the battlefield.  The Austrians are missing only garrisons at Genoa & Alessandria and Vukasovich's Corps (cut off & captured).  The French are missing the Genoa garrison (captured after seige), Victor's 2nd division (on the other side of Alessandria), a few casualties, and some garrison detachments.


Battle of Alessandria

Both sides went into the battle unaware of the exact size of the the enemy force & thinking they are outnumbered.  Only the French actually were.  At dawn on the day of the battle the Austrians had 60,000 men on the field while the French still had less than 20,000 - Suchet & Moncey in the north & Murat's cavalry on the Valenza Road in the south.  But more French infantry were working their way through the wooded hills on the Austrian right flank.  The Austrians had to suspect this, as it was the only place their cavalry had been unable to reconnoiter the day before.  But even with their redeployment, the French could only get 55,000 men onto the field.  The contrast between the attitude of the two sides leading up to the battle was stark - the Austrians had a bad case of MacClellan's syndrome while Bonaparte was determined to fight, betting that a strategic advantage would outweigh any lack of numbers.

The Austrians had a number of options, including:
#1. Attack Suchet & Moncey & defeat them before the French reinforcements could arrive.
#2. Make a fighting withdrawal to Alessandria.
#3. Redeploy to face the French attack & beat it off.

#1 would have left the Austrian line of supply vulnerable, but defeat of the French right would have given the Austrians superior numbers to attack & restore it.  Knowing the full picture, it's obvious that they should have done this immediately they found Suchet & Moncey's position 2 days before.  But even on the day of battle the Austrians would maintain a large advantage in numbers until mid morning.
#2 would hand Bonaparte a propaganda victory, but with such superior numbers at the start, the Austrians should have been able to retreat in good order & so keep their army able to fight another day in more favourable circumstances.
#3 is what the Austrians tried to do.  They stood on the defensive facing Suchet & Moncey & moved the rest of their army south to cover the road to Alessandria.

The blogs of 27/05 & 02/06 describe the 1st phases of the battle fought over two nights.  The map below shows situation about noon when we started night 3.
During the morning:
- The Austrians have moved their reserves to the right to protect their LOC.
- Suchet & Moncey have put pressure on the Austrian left.
- Bonaparte held Bessierses & Victor back until the Austrians were over-committed to their right.
- Bessieres & Victor have punched hole though the Austrian centre.

At this stage the morale of the Austrian players was completely shot & they ordered a withdrawal. 
Overview at the the start of the night's action.
On the Austrain left they have moved some cavalry to the right to cover the retreat as the infantry try to pull out of the village. 
 On the Austrian right they have neumerical superiority, but with their left collapsing they are just holding the line to allow their centre to retreat.  
In the centre the Austrian grenadiers are stopping Victor's advance, but the Austrians in the village are being pincered between Bessieres & Suchet. 
 The remains of the Austrian left has fled. One square remains covering the retreat.
The Austrian left has is slowly backing off as their centre marches off.

Given their numerical advantage the Austrian plan could have worked, but they made too many mistakes.  These included:
- The force they sent south was larger than the French flanking force, yet they didn't attack.  Instead they let the fight on that front be an indecisive exchange between artillery & skirmisher lines.
- They arguably had more troops than they needed in Castello Montefrato.
- The redeployment left a weak spot in the line where it made a dogleg behind Castello Monteferato.

The French plan was to draw the Austrian reserves south, put pressure on the Castello Monteferato position & cut the Austrian left off with an attack behind the dogleg in the Austrian line & it worked.

The decisive French win means that Melas has no choice but to retreat into Alessandria & ask for terms.  The campaign is over & Bonaparte is going to be an emperor.


1 comment:

KEV. Robertson. said...

Hi Jim- This is a huge Battle - remarkable amount of Painting. I've a soft spot for the Austrians having visited Austria in 2015 during the May season. Cheers. KEV.