It flourished at around the same time as the Egyptian pyramids were being built.
—This time line is based on the standard Egyptologist boilerplate history which gets its dates from several Kings lists, one of which is known to be a fake. The dates are assumes much the same way as the Christian fundamentalists count by years reigned and name.
The trouble here is not only the aforementioned fake list, but also that Egyptians kings often changed their names several times or took the name of a previous king. Worse there are kings listed who are unknown in the archeological record.
On top of that there is some evidence (bio-thermoluminescence dating) that the standard dates attributed to the Giza pyramids are wrong and they are much older, which screws up the whole King-that-built-it meme. Moreover, the entire complex could only have been planned and built as a unit, not as separate structures built over time (interlocking mathematical patterns, casting of critical and significant shadows, etc).