Complex sentence: Both Xing and Amestris were taught the initial concepts of their versions of alchemy by mysterious figures from a foreign land-the Amestrians had the "Eastern Philosopher" (possibly Father), the Xingese had the "Western Sages" (possibly Van Hohenheim).
Split into simpler sentences: Both Xing and Amestris were taught the initial concepts of their versions of alchemy by mysterious figures from a foreign land. The Amestrians had the "Eastern Philosopher" (possibly Father), the Xingese had the "Western Sages" (possibly Van Hohenheim).