Changes

Although the first professional armies were likely founded in the 3rd millennium BC, what we can see is that increasingly by the 2nd millennium BC the use of foreigners and elite soldiers and officers were used within military units. Increasingly throughout the 1st millennium BC , armies became more consistently professional with full time soldiers and specialized troops. Another important development was the infrastructural developments that facilitated the movement and equipping armies, including roads and armories. This facilitated warfare by not making it bound by the agricultural cyclesthat would have limited when armies could fight. This also enabled far larger empires to now emerge in the Old World, starting first with the Neo-Assyrian Empire and continuing to the Roman and even later empires. The success of creating professional armies, consisting of foreign volunteers and mercenary forces, and having specialized units of officers was first developed by the Assyrians with later states building upon the Neo-Assyrian system.