Relative empire power (composite score scaled 0–1 vs all-time peak) shows: Netherlands dominated 1600–1650, then declined as UK rose; UK peaked ~1900, then declined as US rose; China declined from historical highs starting ~1600 and has been rising since Deng reforms (~1980). The pattern suggests 75–100 year cycles from rise to decline. The US appears to be in or past its top phase; China is in its ascent phase — the current analog to the 1930–1950 UK-to-US transition.