Many Italians fought a guerrilla war in "Africa Orientale Italiana", after the surrender at Gondar of the last regular Italian forces in november 1941.
They fought in the hope of an Italian victory with the help of Rommel in Egypt and in the Mediterranean (called in 1942 by Mussolini "the Italian Mare Nostrum"), that would originate a possible return of the Axis in Eastern Africa.
In the first months of 1941 he fought the invasion of the British forces in Assab and Dancalia (southern Eritrea), but did not surrendered and decided to hide in the mountains in order to continue the war as a "resistance fighter".
He partecipated actively in the Italian guerrilla war in Ethiopia and Eritrea during 1941 and 1942.
In january 1942 captain De Martini blew up an important ammunition deposit in Massaua (Eritrea) and later, captured by the British, was able to escape to Yemen. From there, he organized a group of eritrean sailors (with little boats called "sambuco") in order to identify - and notify Rome with his own radio - the british navy movements throughout the Red Sea.
In august 1942 captain De Martini returned in a "sambuco" to the coast of Eritrea, where he did some guerrilla sabotages with his eritrean sailors but was captured.
After the end of WWII, Captain Francesco De Martini received the italian golden medal of honor .