Complex sentence: Her major field of research was prehistoric Mycenaean civilization, with an emphasis on Laconia, Sparta where she participated in a survey and the excavation of the palace of Menelaus.
Split into simpler sentences: Her major field of research was prehistoric Mycenaean civilization, with an emphasis on Laconia, Sparta. At Laconia, she participated in a survey and the excavation of the palace of Menelaus.