|Centuries:||16th century – 17th century – 18th century|
|Decades:||1590s 1600s 1610s – 1620s – 1630s 1640s 1650s|
|Years:||1618 1619 1620 – 1621 – 1622 1623 1624|
- February 9 – Gregory XV is elected pope.
- February 17 – Miles Standish is appointed as first commander of Plymouth Colony.
- March 16 – Samoset, a Wampanoag, visits the settlers of Plymouth Colony and greets them, "Welcome, Englishmen! My name is Samoset."
- March 22 – The Pilgrims of Plymouth Colony sign a peace treaty with Massasoit of the Wampanoags.
- April 5 – The Mayflower sets sail from Plymouth on a return trip to Great Britain.
- The Swedish city of Gothenburg is founded by Gustavus Adolphus
- Riga falls under rule of Sweden
- Willebrord Snell discovers the laws of refraction.