June 21
day of the year
June 21 is the 172nd day of the year (173rd in leap years) in the Gregorian calendar; 193 days remain until the end of the year.
It is the most common day on which the June solstice occurs, in the astronomical reckoning the first day of summer in the Northern Hemisphere and of winter in the Southern Hemisphere.
Events
Pre-1600
217 BC – A Carthaginian force under Hannibal ambushes and defeats a Roman army commanded by Gaius Flaminius in the battle of lake Trasimene during the Second Punic War.
533 – A Byzantine expeditionary fleet under Belisarios sails from Constantinople to attack the Vandals in Africa, via Greece and Sicily.
870 – Caliph al-Muhtadi is killed by rebellious troops and is succeeded by his cousin Al-Mu'tamid.
1307 – Külüg Khan is enthroned as Khagan of the Mongols and Wuzong of the Yuan.
1529 – French forces are driven out of northern Italy by Spain at the Battle of Landriano during the War of the League of Cognac.
1582 – Sengoku period: Oda Nobunaga, the most powerful of the Japanese daimyōs, is forced to commit suicide by his own general Akechi Mitsuhide.
1601–1900
1621 – Execution of 27 Czech noblemen on the Old Town Square in Prague as a consequence of the Battle of White Mountain.
1734 – In Montreal, New France, a slave known by the French name of Marie-Joseph Angélique is put to death, having been convicted of setting the fire that destroyed much of the city.
“June 21” enters the record as day of the year. Crown Archives preserves that source wording while asking what June and year can confirm, complicate or overturn.
Why this record matters
“June 21” is worth following because a concise public description often conceals a longer documentary argument. Here, June and year provides the most credible route into that argument.
Vocabulary and entity names are the principal evidence signals here, because they determine the precision of every later search. The source revision retrieved here is dated Sep 8, 2026. The linked authority identifier is Q2671. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1600, 1307, 1529 and 1582.
A concise general-reference account can conceal disagreements about scope, terminology or the weight assigned to individual sources. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
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This entry incorporates text from “June 21” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.