Editing 1721 (section)

=== April–June ===
* [[April 4]] &ndash; [[Robert Walpole]] becomes the first [[Prime Minister of Great Britain]] (although this is more a term of disparagement at this time).<ref>{{cite web|title=Sir Robert Walpole|url=http://www.number10.gov.uk/history-and-tour/sir-robert-walpole/|work=10|publisher=HM Government|access-date=2011-11-16|archive-url=https://web.archive.org/web/20111101195959/http://www.number10.gov.uk/history-and-tour/sir-robert-walpole/|archive-date=November 1, 2011|url-status=dead|df=mdy-all}}</ref>
* [[April 21]] &ndash; The deadliest [[1721 Boston smallpox outbreak|outbreak of smallpox]] in the history of [[Boston]] begins when the British ship HMS ''Sea Horse'' arrives in Boston Harbor with a crew of sailors who had survived a smallpox epidemic.  One of the ''Seahorse'' crew who had cleared quarantine develops symptoms the next day and infects other people in a lodging house.  Over the next 10 months, 5,759 cases of smallpox are recorded in Boston and 844 people die of the disease.
* [[April 26]] &ndash; [[Pirate]]s [[John Taylor (pirate)|John Taylor]] and [[Olivier Levasseur]] capture the 700-ton [[Portugal|Portuguese]] [[galleon]] ''Nossa Senhora do Cabo'' at [[Réunion]]. The total value of treasure on board (from [[Portuguese Goa State|Goa]]) is estimated as between £100,000 and £875,000, one of the largest pirate hauls ever.  <ref>Frank Sherry, ''Raiders and Rebels: The Golden Age of Piracy'' (Quill, 1986) p15 </ref><ref>{{cite book|title=Black Bart Roberts: The Greatest Pirate of Them All|last=Breverton|first=Terry|author-link=Terry Breverton|year=2004|publisher=Pelican Publishing|location=Gretna, LA|isbn=1-58980-233-0|page=57}}</ref> 
* [[May 8]] &ndash; [[Pope Innocent XIII]] succeeds [[Pope Clement XI]], as the 244th [[pope]].
* [[June 26]] &ndash; Dr. Zabdiel Boylston of the [[Harvard University]] School of Medicine begins the first public inoculation campaign in order to slow the [[1721 Boston smallpox outbreak|smallpox epidemic]] in Boston, giving a vaccine to his own son, and then to his slave and the slave's infant son.  <ref>"The Boston Inoculation Controversy of 1721-1722: An Incident in the History of Race", by Margo Minardi, ''The William and Mary Quarterly'' (January 2004)</ref>