* 1721 March – Philip V of Spain requested the restitution of Gibraltar to proceed to the renewal of the trade licences of Great Britain with the Spanish possessions in America.

Pope Clement XI ( 23 July 1649 – 19 March 1721 ), born Giovanni Francesco Albani, was Pope from 1700 until his death in 1721.

Pope Innocent XIII ( 13 May 1655 – 7 March 1724 ) was pope from 1721 until his death.

* March – Joseph de Guignes, French orientalist ( b. 1721 )

* March 26 – John Mudge, English physician and inventor ( b. 1721 )

On 6 March 1711, she was proclaimed a Tsarevna, and on 23 December 1721, a Tsesarevna.

Since Maurice had also given her more serious grounds of complaint against him, he consented to an annulment of the marriage in 21 March 1721.

* Henry Boyle, 1st Baron Carleton ( 25 June 1721 – 27 March 1725 )

* James Stanhope, 1st Earl Stanhope: 16 March 1718 – 4 February 1721

* James Craggs the Younger MP: 16 March 1718-16 February 1721

Bach's dedication to the Margrave was dated 24 March 1721.

He resigned the Exchequer in January 1721, and in March was found guilty by the Commons of the " most notorious, dangerous and infamous corruption ".

March 1721 – 6 February 1775 ) was a British politician.

10 June 1657 – 16 March 1721 ) was an English politician and the father of James Craggs the Younger.

John Mudge ( 1721 – 26 March 1793 ) was an English physician and amateur creator of telescope mirrors.

* Infanta Mariana Victoria of Spain ( 31 March 1718 – 15 January 1781 ) was the eldest daughter of Philip V of Spain and his second wife Elisabeth of Parma ; born in Madrid, she moved to France in 1721 and lived at the Tuileries Palace in Paris with her proposed husband ; the engagement was broken off due to tense relations regarding the marriages of the Regents daughters marrying to of Philip V's sons.

* Charlotte Lee, Lady Baltimore ( 13 March 1678 ( Old Style ) – 22 January 1721 ), first married to Benedict Calvert, 4th Baron Baltimore and secondly to Christopher Crowe, Consul of Leghorn.

On May 31, 1721, he was beatified, and on March 19, 1729, he was canonized under Pope Benedict XIII.

He died 24 March 1721.

Troubled by the lack of support and communication from London, Rogers set sail for Britain in March 1721.

Mariana Victoria arrived in Paris on 2 March 1721 amongst much celebration and took up residence at the Palais du Louvre.

Joseph de Guignes ( October 19, 1721 – March 19, 1800 ), was a French orientalist, sinologist and turkologist born at Pontoise, the son of Jean Louis de Guignes and Françoise Vaillant.

In March 1721 Charles Bridgeman, James Thornhill, John Wootton and Gibbs were all travelling together from London to Wimpole Hall where they were all working for the Edward Harley Earl of Oxford, Thornhill recalled they drank Harley's " healths over and over, as well in our civil as bacchanalian hours " and talked " of building, pictures and may be towards the close of politics or religion ".

* March 31 – Infanta Mariana Victoria of Spain, queen regent of Portugal ( d. 1781 )

In the same year Charles ' first sister, Infanta Mariana Victoria was born on 31 March.

* Infanta Maria Francisca ( born 3 March 1997 )

* 31 March: Infanta Mariana Victoria of Spain born in Madrid ; later betrothed to Louis XV ;

* 10 March: Arrival of HRH Infanta Mariana Victoria of Spain in Paris ; daughter of Philip V of Spain and Elisabeth of Parma ;

* 23 June 19819 March 1991: Her Royal Highness The Infanta Pilar, Duchess of Badajoz, Viscountess of la Torre

* 9 March 1991present: Her Royal Highness The Infanta Pilar, Duchess of Badajoz, Viscountess Dowager of la Torre

Mariana Victoria of Spain ( 31 March 1718 – 15 January 1781 ) was an Infanta of Spain by birth and was later the Queen of Portugal as wife of King Joseph I.

* 31 March 1718 – 19 January 1729 Her Royal Highness Infanta Mariana Victoria of Spain

The Infanta Margarita of Spain, Duchess of Soria, 2nd Duchess of Hernani, Grandee of Spain ( Doña Margarita María de la Victoria Esperanza Jacoba Felicidad Perpetua y Todos los Santos ( et omnes Sancti ) de Borbón y Borbón-Dos Sicilias ) ( born Rome, 6 March 1939 ), is the younger daughter of Infante Juan, Count of Barcelona and Princess María Mercedes of Bourbon-Two Sicilies, and younger sister of current reigning King Juan Carlos of Spain and Sister of Infanta Pilar, Duchess of Badajoz.

Remotely Operated Vehicle KAIKO reached the deepest area of Mariana trench and made the deepest diving record of 10, 911 m on March 24th 1995.

On 26 March, he reached the bottom of the Mariana Trench in the submersible vessel, the Deepsea Challenger.

* Mariana Trench Dive ( 25 March 2012 ) – Deepsea Challenger.

He was sent to the Mariana Islands on 4 March 1944 as commander in chief of the short-lived Fourteenth Air Fleet, and simultaneously commander in chief of the equally short-lived Central Pacific Area Fleet.

On 25 March 2012, James Cameron reached the Challenger Deep part of the Mariana Trench in the Deepsea Challenger submersible.

XXI Bomber Command, the second B-29 combat command and control organization was formed under Second Air Force in March, 1944 with its combat groups beginning to deploy to the Mariana Islands in the Western Pacific beginning in December 1944.

* Northern Mariana Islands: March – June

Walsh joined the team that oversaw the dive of the Deepsea Challenger mission where James Cameron dove solo to the bottom of the Mariana Trench on March 26, 2012.

Under the influence of the Prime Minister Louis Henri, Duke of Bourbon and his mistress Madame de Prie, the decision was made to send the seven year old Mariana Victoria back to Spain on 11 March 1725.

Benjamin Taisacan Manglona ( born March 31, 1938 ) is a politician and civil engineer in the United States Commonwealth of the Northern Mariana Islands ( CNMI ).

In March 2011, the Northern Mariana Islands House of Representatives adopted House Resolution 17-45, which honored Benjamin Manglona for " his distinguished career in public office and his exemplary contributions to the CNMI.

In March 2012 the AFC announced that the Northern Mariana Islands were approved to participate in the AFC Challenge Cup and AFC President ’ s Cup if they fulfilled the criteria.