He returned to his hometown, whence his dreams had first taken root.

whence 是古英语中保留至今的副词，由 where（哪里）和 hence（从...起）组合演变而来，意思是"从何处来"或"由此处"，在现代英语中多用于正式或文学语境，表示"从那个地方"或"从那时起"。