Ankara headquarters of the Turkish Aerospace Industries, MKE, ASELSAN, Havelsan, Roketsan, FNSS, Nurol Makina, and numerous other firms are located. Exports to foreign countries from these defence and aerospace firms have steadily increased in the past decades. The IDEF in Ankara is one of the largest international expositions of the global arms industry. A number of the global automotive companies also have production facilities in Ankara, such as the German bus and truck manufacturer MAN SE. Ankara hosts the OSTIM Industrial Zone, Turkey's largest industrial park. A large percentage of the complicated employment in Ankara is provided by the state institutions;
Ankara Diocletian (284–305), seems to have engaged in a substantial programme of rebuilding and of road construction from Ankara westwards to Germe and Dorylaeum (now Eskişehir). In its heyday, Roman Ankara was a large market and trading center but it also functioned as a major administrative capital, where a high official ruled from the city's Praetorium, a large administrative palace or office. During the 3rd century, life in Ancyra, as in other Anatolian towns, seems to have become somewhat militarized in response to the invasions and instability of the town. The city is well known during the 4th century as a