In the area of "Old Market", on the southern hill of the city, there was an Early Neolithic settlement (late 7th to early 6th millennium BC). Giannitsa was also inhabited through the Bronze and Iron Ages. Incidental findings, such as coins, inscriptions, and sculptures indicate that the area was inhabited during the Hellenistic period (323-30BC). In ancient times, the area was called Bottiaea.
Though there was probably a pre-existing Byzantine castle in the vicinity, the importance of the city of Yenije begins with its foundation by Gazi Evrenos in around 1372. Yenije became the base of the ghazi followers of Evrenos who took Macedonia and later Albania. The city was an important Ottoman cultural center and sacred area in the 15th and 16th centuries. Starting in the mid-15th century, Giannitsa became a center of literature and the arts. Under Ahmet Bey, a descendant of Gazi Evrenos, many mosques, schools, workhouses and charitable projects were founded.
In the early 20th century, Yenije was a battleground between Bulgarian and Greek-Macedonian partisans in the Macedonian struggle. Penelope Delta's novel Secrets of the Swamp (referring to the shores of Giannitsa Lake) is a romanticised account of this from the Greek point of view.
Yenidje "retained its emphatically Turkish character up to 1912" and members of the Evrenos family lived in the city in a large palace in the center of town until then. In the First Balkan War, the Battle of Yenidje (20 October 1912) was one of the most important battles the Greek army fought.
The German army invaded Giannitsa on April 11, 1941.
On April 20, 1941, some Austrian forces arrived. The municipal registry of Giannitsa confirms four random killings in various parts of the city.
On 16 September 1943, the Municipality of Giannitsa, headed by the Mayor, Thomas Magriotis and the help of local soccer teams organized a demonstration in the city and indulge in German commandant a text against the intention of the Germans to surrender Central Macedonia to the Bulgarians.
According to oral testimony on November 13, 1943, the Germans arrested around 50 people, whom they transferred to the camp of Pavlos Melas at Thessaloniki and they killed thirteen. At the same time, the Germans invaded for the first time the village Eleftherohori 7 km (4 mi) away from the city, steal and destroy. In this attack there were no casualties.
On 23 March 1944, the village was burned, and the place deserted. Eleftherohori lost 19 lives.
On 5 August 1944, the Austrian soldier Otmar Dorne left the German occupation army and joined the 30th Constitution of the E.L.A.S, based in Mount Paiko. The defection of Dorne, and the presence of the SS sergeant Schubert, led to mass reprisals on 14 September 1944 in Giannitsa: about 120 residents of Giannitsa were executed by forces of the Jagdkommando Schubert with the collaboration of Greek units under the command of G. Poulos. Among those executed was the Mayor, Thomas Mangriotis. The Swedish ambassador Timberg indicated that one third of the city was destroyed by fire. The citizens left the city. Emile Wenger visited Giannitsa few days after the mass execution, as a representative of the International Red Cross and wrote "Giannitsa is already a dead city".
On 20 September 1944, a citizens' committee sent a message to the National Government stating the facts and asking for weapons. The Germans left Giannitsa on November 3, 1944.
Source: wikipedia.org