Who installed a pillar at Lumbini in the mid-3rd century BCE?

1. In the mid-3rd century BCE Emperor Ashoka determined that Lumbini was the Buddha's birthplace. 2. He installed a pillar there with an inscription naming the Buddha, sage of the Shakyas. 3. Harsha, Kanishka and Samudragupta belong to later periods. _Source: Wikipedia, Gautama Buddha, Birth and early life_