Complex sentence: The first problem the student of Egyptian chronology faces is that they used no single system of dating: they had no concept of an Era similar to Anno Domini, Anno Hajirae--or even the concept of named years like limmu used in Mesopotamia.
Split into simpler sentences: The first problem the student of Egyptian chronology faces is that the ancient Egyptians used no single system of dating. They had no concept of an Era similar to Anno Domini, Anno Hajirae, or even the concept of named years like limmu used in Mesopotamia.