How many years has it been since 1620?

This is the 21st century when did it become the 21st century? What was the original purpose of the crusaders? What is culvosac? Where did the phragmites originate from? What political problems did rome faced? Which of martin Luther and disagreements with the catholic church was the most influenced by the renaissance idea of humanism answer? How did early humans move from continent to continent? What are some differences between the real west and the mythic west of popular culture? What were the eight different attempts to retake Jerusalem? Who is not included in the definition of civilizations? How did the europeans started to explore and conquer other lands? How yorkton got its name? How many years has January 4th fallen on a Wednesday? What were the main historical causes of the rift between the eastern and western churches? What was a main reason for the Crusades? How did the crusades destroy the empire? What did Mongol journey stations provided food and horses to? How did Charlemagne expand his empire? What was Charlemagne most remembered for? What stayed the same during the crusades?