Complex sentence: In 671 BC crossed the Sinai Desert, and invaded and took Egypt with surprising ease and speed, driving its foreign Nubian/Kushite and Ethiopian rulers out and destroying the Kushite Empire in the process.
Split into simpler sentences: In 671 BC he crossed the Sinai Desert, invaded and took Egypt with surprising ease and speed. He drove its foreign Nubian/Kushite and Ethiopian rulers out, destroying the Kushite Empire in the process.