1621

1621 (MDCXXI) was a common year starting on Friday of the Gregorian calendar and a common year starting on Monday of the Julian calendar, the 1621st year of the Common Era (CE) and Anno Domini (AD) designations, the 621st year of the 2nd millennium, the 21st year of the 17th century, and the 2nd year of the 1620s decade. As of the start of 1621, the Gregorian calendar was 10 days ahead of the Julian calendar, which remained in localized use until 1923.

Millennium:	2nd millennium
Centuries:	16th century – 17th century – 18th century
Decades:	1590s  1600s  1610s  – 1620s –  1630s  1640s  1650s
Years:	1618 1619 1620 – 1621 – 1622 1623 1624

1621 in other calendars

Gregorian calendar	1621 MDCXXI
Ab urbe condita	2374
Armenian calendar	1070 ԹՎ ՌՀ
Assyrian calendar	6371
Balinese saka calendar	1542–1543
Bengali calendar	1028
Berber calendar	2571
English Regnal year	18 Ja. 1 – 19 Ja. 1
Buddhist calendar	2165
Burmese calendar	983
Byzantine calendar	7129–7130
Chinese calendar	庚申年 (Metal Monkey) 4317 or 4257     — to — 辛酉年 (Metal Rooster) 4318 or 4258
Coptic calendar	1337–1338
Discordian calendar	2787
Ethiopian calendar	1613–1614
Hebrew calendar	5381–5382
Hindu calendars
- Vikram Samvat	1677–1678
- Shaka Samvat	1542–1543
- Kali Yuga	4721–4722
Holocene calendar	11621
Igbo calendar	621–622
Iranian calendar	999–1000
Islamic calendar	1030–1031
Japanese calendar	Genna 7 (元和７年)
Javanese calendar	1542–1543
Julian calendar	Gregorian minus 10 days
Korean calendar	3954
Minguo calendar	291 before ROC 民前291年
Nanakshahi calendar	153
Thai solar calendar	2163–2164
Tibetan calendar	ལྕགས་ཕོ་སྤྲེ་ལོ་ (male Iron-Monkey) 1747 or 1366 or 594     — to — ལྕགས་མོ་བྱ་ལོ་ (female Iron-Bird) 1748 or 1367 or 595

Events

• 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.