Passage: Facing pressure from Baekje in the west and Japan in the south, in the later part of the 4th century, Silla allied with Goguryeo. However, when Goguryeo began to expand its territory southward, moving its capital to Pyongyang in 427, Nulji of Silla was forced to ally with Baekje.

Question: Goguryeo moved it's capital to Pyongyang in what year?
427