From The Dhamma Encyclopedia
King Ashoka (304 BC - 232 BC) reigned over all of South Asia and beyond due to many military invasions led by him. He controlled all of present day India, Nepal, Bangladesh, Pakistan, Afghanistan, and Iran. His kingdom was vast. He renounced all violence after becoming a Buddhist. He was a vegetarian and erected many edicts praising the Buddha's teachings which also gave further archeological proof of the Buddha's life and other historical information found in the Buddhist discourses (canon or scriptures).
He was the third emperor of the Mauryan Dynasty and ruled India from 269 to 232 BCE. Shocked by the destruction he had caused by his war with Kàliïga Ashoka converted to Buddhism and spent the remainder of his reign trying to govern his vast realm by spiritual principles. He renounced an aggressive foreign policy, promoted religious harmony, established hospitals, made the judicial system less harsh and sent Buddhist missionaries throughout India and abroad. It was primarily because of Ashoka’s patronage that Buddhism became an India-wide religion as quickly as it did. To make known his various reforms, Ashoka issued a series of edicts and had them inscribed on rocks and huge stone pillars which were set up all over India. These edicts are the earliest decipherable written records from ancient India.
Maha Bodhi Temple
It is reported that Ashoka built 84,000 edicts, monuments, and stupas honoring his legacy and the Buddha's teachings. If it were not 84,000 it certainly would have been at least a large number. King Ashoka spent one full week just gazing at the Bodhi Tree in Bodh Gaya. Considering this, we can say with virtual certainty that the original Maha Bodhi Temple must have been built by King Ashoka. The temple that we see today has been repaired and renovated throughout history, but the design and placement may be very similar enough that we could credit Ashoka with the establishment of the Maha Bodhi Temple at about 250 BCE.