Original: Between 400,000 years ago and the second interglacial period in the Middle Pleistocene, around 250,000 years ago, the trend in skull expansion and the elaboration of stone tool technologies developed, providing evidence for a transition from H. erectus to H. sapiens.
Simplified: Between 400,000 years ago and the second interglacial period in the Middle Pleistocene, around 250,000 years ago, its skull grew and technologies based on  stone tools developed.