The fourth millennium BC includes the beginning of Bronze age civilization and the beginnings of recorded, written history. At my present stage of development, this is largely concentrated on Egyptian civilization and culture, but I do have references to developing civilizations in Pakistan and China.
At this point, I am shifting to antiquity. Antiquity has much finer subdivisions than prehistory does. The subdivisions of Antiquity are at the level of individual centuries. This is not quite fine enough to work with a conventional narrative history, but summaries of the major peoples and historical figures are possible. Beginning in the early 3rd millennium BC, I can examine the 30th century BC.
Other history can be used to consider the 30th century BC. I have added a few comments about sources. In the 19th century and 20th century, written history has been supplemented by archaeology. I still have a focus on Egypt and the first dynasty. Harappan civilization was developing in Pakistan and India, but since the writing has not been deciphered and translated, its history is not well known.