**The Contribution of Diocletian and Constantine**

Diocletian and Constantine were two influential Roman emperors who ruled during the late 3rd and early 4th centuries. They made significant contributions to the Roman Empire, particularly in terms of political and administrative reforms, military strategies, and the promotion of Christianity.

**Diocletian's Contributions**

1. **Tetrarchy:** Diocletian introduced the concept of tetrarchy, meaning "rule by four." He divided the Roman Empire into four regions, each with its own emperor and co-emperor. This system aimed to provide better administration and defense by sharing power and responsibilities.

2. **Administrative Reforms:** Diocletian reorganized the administrative structure of the empire. He increased the number of provinces and established new administrative divisions to improve governance and control. This helped in better management of resources and taxation.

3. **Economic Reforms:** Diocletian implemented economic reforms to stabilize the empire. He introduced price controls, fixed wages, and attempted to regulate the economy through state intervention. However, these measures were not successful in the long term.

4. **Persecution of Christians:** Diocletian initiated one of the most severe persecutions of Christians in Roman history. He issued a series of edicts ordering the destruction of Christian churches, confiscation of their properties, and the imprisonment and execution of Christian leaders. However, this persecution ultimately failed to eradicate Christianity.

**Constantine's Contributions**

1. **Edict of Milan:** Constantine issued the Edict of Milan in 313 CE, granting religious toleration to Christians and ending the persecution they faced. This was a significant step towards the eventual establishment of Christianity as the state religion of the Roman Empire.

2. **Foundation of Constantinople:** Constantine founded the city of Constantinople (modern-day Istanbul) in 330 CE. This new capital became the seat of power for the Eastern Roman Empire, ensuring its survival for centuries after the fall of the Western Roman Empire.

3. **Christianity as State Religion:** Constantine played a crucial role in the recognition and promotion of Christianity. He legalized Christianity, supported its growth through building churches, and convened the Council of Nicaea in 325 CE to settle theological disputes and establish key Christian doctrines.

4. **Military Reforms:** Constantine implemented significant military reforms, including the creation of a new mobile field army known as the comitatenses. He also introduced the policy of recruiting barbarian soldiers into the Roman army, which helped strengthen and diversify its forces.

Overall, the contributions of Diocletian and Constantine had a lasting impact on the Roman Empire. Diocletian's administrative and economic reforms aimed to stabilize the empire, while Constantine's religious policies played a crucial role in the rise of Christianity and the transformation of the Roman Empire into a Christian state.