Simeone Marsan was born on 24 August 1911 and was from Zara.

Marsan was commissioned (in Servizio Permanente Effettivo) on 1 October 1932.

On the last day of August 1940, the 151^o Gruppo C.T. (366^a, 367^a and 368^a Squadriglie) was ordered to move in Libya with 30 CR.42s as a reinforcement for the attack against Sidi Barrani.
The unit under the command of Maggiore Carlo Calosso was one of the first equipped with CR.42s in 1939 and was based in Caselle Torinese near Turin, with sections and Squadriglie detached in different airbases of North Italy for local defence duties.
They departed Caselle Torinese in the morning of 6 September and at 18:20 on 8 September, the whole Gruppo landed in Tripoli Castel Benito.
The 366^a Squadriglia formation was composed of ten aircraft: Capitano Bernardino Serafini (CO), Tenente Mario Ferrero (the Gruppo Adjutant), Sottotenente Amedeo Guidi, Maresciallo Giulio Cesare, Sergente Maggiore Fiorenzo Milella, Sergente Maggiore Dino Carta, Sergente Maggiore Roberto Marchi, Sergente Maggiore Cesare Chiarmetta, Sergente Antonio Camerini, Sergente Eugenio Cicognani. Tenente Piero Veneziani and Maresciallo Giovanni Accorsi followed in the unit’s hack Caproni Ca.133 together with five ground personnel.
The formation of 367^a Squadriglia comprised the Gruppo Commander Maggiore Carlo Calosso, the 368^a Squadriglia’s pilot Sergente Piero Hosquet and nine other pilots for a total of eleven. Among them were Capitano Simeone Marsan (the CO), Tenente Irzio Bozzolan, Tenente Aldo Bonuti, Sergente Maggiore Gino Bogoni and Sergente Tolmino Zanarini. The Squadriglia’s other six pilots were Tenente Giuseppe Costantini, Maresciallo Bruno Castellani, Sergente Maggiore Rodolfo Benco, Sergente Maggiore Bruno Celotto, Sergente Renato Mingozzi and Sergente Maggiorino Soldati.
The 368^a Squadriglia formation was composed of nine aircraft: Capitano Bruno Locatelli (CO), Tenente Giuseppe Zuffi, Sottotenente Furio Lauri, Sergente Maggiore Davide Colauzzi, Sergente Maggiore Annibale Ricotti, Sergente Maggiore Alvise Andrich, Sergente Stefano Fiore, Sergente Ottorino Ambrosi, Sergente Mario Turchi. Tenente Orfeo Paroli and Maresciallo Guido Paparatti followed in the Ca.133 of the Squadriglia (Paroli and Fiore were just transferred from 367^a Squadriglia).
On 25 September the 151^o Gruppo transferred from Benghazi to El Adem where it replaced the 9^o Gruppo C.T.

Starting from 09:00 on 19 December, nine Hurricanes from 274 Squadron took off with fifteen minutes intervals during the morning. Then at least seven others took off for a second mission, this time taking off with 25 minutes intervals. Although explicitly ordered to keep clear of fighters they engaged CR.42s on two separate occasions during the day.
Second Lieutenant Talbot (P3721) claimed a confirmed victory over a CR.42. He was flying at 17,000 feet, 30 miles west of Bardia (Great Gambut) when at 13:05 he discovered two formations of six CR.42s stepped up to right and flying one mile to starboard. He approached unobserved and attacked a straggler of the formation. He reported:

“attacked by remainder of formation. 1 CR 42 spiralled down after attack and was later seen burning on the ground by Flying Officer Greenhill. CR 42s where on offensive patrol not escorting bombers.”

“the CR 42s were 11 or 12 in a bunch (no formation). I delivered an attack from astern and the enemy immediately attacked, 1 CR 42 was badly damaged (probably shot down), 6 holes in own aircraft through main spar. Enemy a/c on offensive patrol showing determination. Holes in own aircraft about 303 size (1 e/a seen burning after engagement by 2nd Lieutenant Talbot).”

On 20 December, the 366^a Squadriglia discovered that most of its fighters needed a thoroughly engine revision at a S.R.A.M and were not repairable in the Squadriglia. The 367^a Squadriglia detached its only three combat ready CR.42s to Z1, to fly with the 4^o Stormo; five pilots accompanied the fighter with Capitani Marsan and Giuseppe Costantini leading them. Two fighters of the 368^a Squadriglia (one flown by Tenente Furio Lauri) were also detached to Z1.

On 12 February 1941, the last 12 airworthy CR.42s of the 151^o Gruppo were pulled out of the frontline and sent west to Sorman airfield, on the Libyan coast. Here the unit was placed under the command of Tenente Colonnello Raffaele Colacicchi, who had taken over from Maggiore Calosso in the December when the latter stood down due to ill health. The three squadriglie commanders were Capitano Bernardino Serafini (366^a), Capitano Marsan (367^a) and Tenente Giuseppe Zuffi (368^a).

On 8 June 1942, he was promoted to Maggiore.

On 15 August 1942, Maggiore Marsan was posted to the 4^o Stormo, handing over the temporary command of the 101^o Gruppo Tuffatori to Capitano Carlo Alberto Rizzi.

In a mission between 15:30-17:10 on 18 September, Maggiore Marsan led 16 MC.202s from the 9^o Gruppo (eight each from the 73^a and 96^a Squadriglie) on a free sweep south of El Alamein. They met Spitfires over El Alamein, with ten Spitfires at 7 000 meters altitude and ten more flying 2 000 meters lower. The 73^a Squadriglia claimed three shot down without losses. One was claimed by Sergente Teresio Martinoli. The second was shared by Sergente Armando Angelini, Maresciallo Paolo Perno and Sergente Leonardo Rinaldi. The third was shared by Maggiore Marsan, Maresciallo Salvatore Mechelli, Tenente Giuseppe Oblach, Tenente Giulio Reiner and Tenente Vittorio Squarcia.
It seems that they had been in combat with Spitfires from 145 and 610 Squadrons, which reported meeting eight fighters identified as Bf 109s over Burg el Arab at 16:55. 145 Squadron made three claims when Flight Sergeant Edgar Andrew Kerr (Spitfire Vb AR287/ZX-K) claimed a probable, Flight Lieutenant John Stuart Taylor (AB147/ZX-Y) claimed a damaged and Sergeant P. G. C. Thomas (BP986/ZX-X) claimed a probable. Flight Lieutenant Mervin Robert Bruce Ingram (Spitfire Vc AR289/P) from 601 Squadron also claimed a probable. The Spitfires returned without losses.

In 1943, he served in the 5^o Stormo.

Marsan ended the war with 1 shared probable biplane victory and a total of 1 shared destroyed.

Claims:

Kill no.	Date	Time	Number	Type	Result	Plane type	Serial no.	Locality	Unit
	1940
	19/12/40	12:15-14:15	1/11	Hurricane (a)	Shared probable	Fiat CR.42		S Sidi Azeiz	367a Squadriglia
	19/12/40	12:15-14:15	1/11	Hurricane (a)	Shared damaged	Fiat CR.42		S Sidi Azeiz	367a Squadriglia
	19/12/40	12:15-14:15	1/11	Hurricane (a)	Shared damaged	Fiat CR.42		S Sidi Azeiz	367a Squadriglia
	1942
	18/09/42	15:30-17:10	1/5	Spitfire (b)	Shared Destroyed	MC.202		El Alamein	73a Squadriglia

Biplane victories: 1 shared probably destroyed, 2 shared damaged.
TOTAL: 1 shared destroyed, 1 shared probably destroyed, 2 shared damaged.
(a) Claimed in combat with Hurricanes from 274 Squadron, which claimed 1 and 1 probable CR.42 without losses. 151^o Gruppo claimed 1 probable and 2 damaged Hurricanes while suffering 1 badly damaged CR.42 and 2 lightly damaged. The 70^a Squadriglia claimed 1 damaged Hurricane while suffering 1 damaged CR.42.
(b) Probably claimed in combat with Spitfire Vs from 145 and 601 Squadron, which claimed 2 probable Bf 109s and 1 damaged without losses. 73^a Squadriglia claimed 3 destroyed Spitfires without losses.

Sources:
A History of the Mediterranean Air War 1940-1945: Volume Two – Christopher Shores and Giovanni Massimello with Russell Guest, Frank Olynyk & Winfried Bock, 2012 Grub Street, London, ISBN-13: 9781909166127
Annuario Ufficiale Delle Forze Armate Del Regno D’Italia Anno 1943. Part III Regia Aeronautica – 1943 Istituto Poligrafico Dello Stato, Roma
Desert Prelude: Early clashes June-November 1940 - Håkan Gustavsson and Ludovico Slongo, 2010 MMP books, ISBN 978-83-89450-52-4
Desert Prelude: Operation Compass - Håkan Gustavsson and Ludovico Slongo, 2011 MMP books, ISBN 978-83-61421-18-4
Elenco Nominativo dei Militari dell’ A. M. Decorati al V. M. Durante it Periodo 1929 - 1945 2 Volume M - Z
Fiat CR.42 Aces of World War 2 - Håkan Gustavsson and Ludovico Slongo, 2009 Osprey Publishing, Oxford, ISBN 978-1-84603-427-5