The Middle Ages spanned from around 500 to 1500 AD. This period followed the collapse of the Western Roman Empire in 476 AD, leaving Europe without strong central governments. Society was dominated by the Catholic Church and a feudal system led by kings, lords, and serfs. Significant developments included the building of castles, cathedrals, and the Crusades, as well as the introduction of ideas and goods from Muslim civilizations. The period was drastically impacted by the Black Death plague in the 14th century, which killed around one-third of Europe's population and contributed to the end of feudalism. Notable figures that traveled during this time include Joan of Arc and Marco Polo.