Skip to content

Why Does January First Start the New Year? - New Year's Explained

2016-01-01 · explainer · Hank · 3:57 · watch on YouTube

Topic: History & curiosities · mode: Explainer · tags: calendar ritual, self correction, civic or action cta

Hank explains that January 1 starts the year because of Roman calendar history: Numa Pompilius's added months, Caesar and Sosigenes's solar calendar pinned to a new moon after the solstice, and Gregory XIII and Lilius's leap-year fix.

What is said

The parts of the video and what is said in each (★ — how much it matters to the video).

00:00:00 — Happy New Year; why January 1 and not the solstice; cultures simply picked a start date

  • ★★ Hank asks why the year starts on January 1, and why not on the solstice; the answer, he says, involves three people viewers have never heard of. — 00:00:10
  • ★★ Hank says the Earth's orbit has no beginning or end, so cultures have traditionally just picked a start of the year, different cultures choosing different dates. — 00:00:24 · Earth

00:00:44 — The old ten-month Roman lunar calendar, the 51-day gap, Numa Pompilius adds January and February

  • ★★ Hank says that in 46 BC Julius Caesar had just become the first emperor of Rome and the Roman calendar was a mess. — 00:00:44
    • check: first emperor of Rome — slip of the tongue
  • ★★ Hank says the old Roman calendar was hundreds of years old, began with ten months (March first, December last) and was lunar, each month running new moon to new moon. — 00:00:51
  • ★★ Hank says the Romans realigned lunar and solar years with 51 days of buffer time between December and March that belonged to no month. — 00:01:08
  • ★★★ Hank says Numa Pompilius, an early king of Rome, added January and February at the start of the year in the 700s BC, making January 1 the Roman New Year. — 00:01:16
    • a number in question (doubtful): "700's BC" — check against the recording
  • ★ Hank says the month names' Latin number prefixes no longer matching their positions is an immense source of frustration for him. (playful) — 00:01:29

00:01:42 — Calendar drift; Julius Caesar and Sosigenes adopt a 365.25-day solar calendar; January 1 set on the new moon after the solstice

  • ★★ Hank says the Roman New Year kept drifting because lunar and solar cycles did not match, so Romans kept changing month lengths and sometimes adding extra months. — 00:01:42
  • ★★★ Hank says Caesar consulted the Alexandrian astronomer Sosigenes, who proposed an Egyptian-style solar calendar: a 365.25-day year as 365 days with a leap day in February every four years. — 00:02:04
  • ★★★ Hank says Caesar set January 1 not on the solstice but on the nearest new moon, about nine days later, so a new moon of 45 BC fixed the date. — 00:02:27
  • ★★ Hank says the solar year is slightly shorter than 365.25 days, so drift resumed, and by the Middle Ages people celebrated New Year whenever they liked. — 00:02:50

00:02:55 — Renewed drift; Pope Gregory XIII and Aloysius Lilius fix the leap years; thanks to the forgotten three

  • ★★★ Hank says in 1582 Pope Gregory XIII, on astronomer Aloysius Lilius's proposal, mandated the Gregorian calendar: 97 leap years per 400 years instead of 100; it is still basically used. — 00:03:00
  • ★ Hank thanks Numa Pompilius, Sosigenes and Aloysius Lilius for their contributions and apologises that everyone has forgotten them. (playful) — 00:03:25

00:03:32 — Vlogbrothers' tenth year; Hank's survey on what vlogbrothers should do next year; sign-off

  • ★★ Hank notes the brothers are entering 2016, their tenth year of vlogging on YouTube. — 00:03:32 · Vlogbrothers, YouTube
  • ★★ Hank finds comments on John's last video too unscientific a measure, so he has set up a survey, linked in the description, on what vlogbrothers should do next year (2017). — 00:03:39 · Vlogbrothers

In the description and comments

  • ★★ Hank's description corrects him: Caesar was not technically Rome's first emperor; he was dictator for life, and his successor Augustus founded the monarchy. — video description
  • ★★ Hank says that arbitrary things can still be valuable: New Year's is a lovely holiday he is happy to celebrate, even though its date is not special except as the new moon of 2061 years ago. — video description

Threads in this video

Where the stories that moved here went next

Mentioned

Central: Gregorian calendar · Julian calendar · Julius Caesar (Roman statesman) · New Year's Day

Also: People: Aloysius Lilius · Numa Pompilius · Pope Gregory XIII · Sosigenes of Alexandria

Organizations: YouTube

Concepts: leap year · lunar calendar

Places: Ancient Egypt · Ancient Rome · Earth · Sun (star)

Events: winter solstice

Policies: Roman calendar

Only in the description or credits: Augustus

Replies to

← Previous: How to Give Away Over a Million Dollars · Next → Who Owns Oregon? Some Historical Context on the so-called Militia Occupation of Public Lands