Quarantine as a concept is centuries old, but if you’re asking “when did quarantine start” you’re almost certainly thinking of the Covid‑19 period rather than medieval plague rules.

Short answer

Most people date the start of “the Covid quarantine” to around mid‑March 2020 , when many countries and US states issued stay‑at‑home orders, closed schools, and shut non‑essential businesses.

What “quarantine” actually means

Historically, quarantine means separating people or goods that might be infected, to see if they get sick, as opposed to isolation , which is for people already known to be sick.

  • The term comes from the Italian quarantino , a 40‑day period of isolation used in Italian port cities against plague.
  • Medieval cities like Dubrovnik (Ragusa) and Venice were using formal quarantine systems as early as the late 1300s–1400s.

So in one sense, “quarantine” started in 1377 in Ragusa when officials ordered incoming travelers to remain isolated before entering the city, and by 1448 Venice had standardized a 40‑day quarantine , which is where the modern word comes from.

Covid‑19: when did that quarantine start?

For Covid‑19, there isn’t one single global start date, because each country (and often each region) set its own rules at different times.

However, in everyday conversation online, when people say things like “it’s been 5 years since quarantine started,” they usually mean:

  • March 2020 , especially
  • The week of March 13–20, 2020 , when many places in North America and Europe suddenly:
    • Canceled in‑person school
    • Told people to work from home
    • Closed restaurants, bars, and events
    • Issued “stay‑at‑home,” “lockdown,” or “shelter in place” orders

You’ll often see posts marking mid‑March as the “anniversary” of the start of Covid quarantine, because that’s when daily life changed all at once for huge numbers of people.

Historical vs Covid usage (quick view)

[9][1][3][5] [5][7][9] [7] [8][4]
Meaning of “when did quarantine start?” Approximate date Where / context
First formal quarantine in history 1377 Ragusa (now Dubrovnik, Croatia), laws requiring isolation of arrivals from plague‑hit areas.
Word “quarantine” (40‑day rule) 1400s (by 1448) Venetian Senate extends isolation to 40 days, giving rise to the term *quarantino* → quarantine.
Colonial American quarantine laws 1600s Port cities like New York begin using quarantine to control smallpox and other diseases.
Everyday sense: start of “Covid quarantine” Mid‑March 2020 Waves of stay‑at‑home orders, school closures, and lockdowns in many countries.

How people talk about it on forums

In Reddit‑style discussions, people usually anchor the “start of quarantine” to:

The day schools closed and we got told we weren’t coming back after spring break.

or

That week in March 2020 when everything shut down at once.

Threads often mark March 13 as a symbolic date in the US and parts of Europe, even though some regions locked down a bit earlier or later.

TL;DR

  • Historically, quarantine in the strict sense starts in 1377 in the port of Ragusa, and is formalized as a 40‑day quarantino by Venice in the 1400s.
  • In modern conversation, “when did quarantine start” almost always refers to mid‑March 2020 , when Covid‑19 stay‑home orders and shutdowns began in many places.

Bottom note: Information gathered from public forums or data available on the internet and portrayed here.