1604

January–March

• January 1 - The earliest recorded performance of William Shakespeare's play A Midsummer Night's Dream takes place at Hampton Court prior to the main presentation, The Masque of Indian and China Knights, which is performed by courtiers of King James.
• January 14 - The Hampton Court Conference is held between James I of England, the Anglican bishops and representatives of the Puritans. Work begins on the Authorized King James Version of the Bible and revision of the Book of Common Prayer.
• February 14 - King James of England denounces the Roman Catholic Church after learning from one of his spies, Sir Anthony Standen, that Queen Anne has been sent a rosary from the Pope.
• February 17 - King James issues an order for all Jesuits and all Roman Catholic priests to leave his kingdom by March 19.
• February 24 - At Linköping in Sweden, the Riksdag declares that Sigismund, Grand Duke of Lithuania and King of Poland, who has been absent for five years, has effectively abdicated as King of Sweden, and recognizes Karl, Duke of Södermanland, as the new monarch.
• March 15 - More than seven months after their July 25, 1603 coronation, King James I and Anne, Queen consort make the traditional Royal Entry to London. The ceremonies have been postponed from 1603 because of the ongoing plague.
• March 19 - King James opens his first parliamentary session as King of England. In his opening speech to the "Blessed Parliament", the King makes clear that he wants to bring a legal union between England and Scotland and that he does not wish to be "a husband to two wives." The House of Commons refuses to agree with him on the unification of the crown or on the funding that the King requests.
• March 22 - Karl IX begins his reign as King of Sweden.

  April–June

• April 9 - On the first day of the new year 966 M.E. on the Burmese calendar, King Nyaungyan Min of Burma makes a triumphant return to his capital at Inwa after his victory in the war against the principality of Mongnai, one of the Shan States between Burma and Siam
• April 17 - Tsar Dmitry of Russia makes a public conversion to Roman Catholicism in order to attract the aid of Jesuits in his attempt to rule all of Russia.
• April 18 - Maurice of Nassau assembles a combined army of 7,000 Dutch and 4,000 English soldiers to make an attack on the Spanish Netherlands.
• May 19 - Maurice of Nassau begins the Siege of Sluis, a port in the Spanish Netherlands, with 11,000 Dutch and English troops. Despite reinforcements from Spanish relief troops, the city surrenders after three months, with both sides having lost hundreds of casualties.
• May 20
• *Five conspirators in England, led by Robert Catesby, who has invited Thomas Wintour, John Wright, Thomas Percy and Guy Fawkes, meet at the Duck and Drake Inn in London to make a plan for the assassination of King James.
• *Peace discussions between England and Spain begin at Somerset House in London to end the Anglo-Spanish War after 19 years of fighting.
• May 22 - English entrepreneur Charles Leigh and a crew of 46 arrive in South America at what is now the Oyapock River in French Guiana after traveling on the ship Olive Plant. The 35 men and boys who stay create a colonial settlement which they call Oliveleigh, and make a claim to all of the area.
• June 9 - Thomas Percy, one of the English conspirators in the Gunpowder Plot to assassinate King James I, is appointed as one of the king's bodyguards by the Earl of Northumberland.
• June 15 - Ottoman–Safavid War: General Cigalazade Yusuf Sinan Pasha, commander of the eastern Ottoman Army, leads troops on a march from Constantinople to fight the Persia's Safavid Army in Armenia, but arrives too late to save the city of Yerevan.
• June - Ottoman–Safavid War : Shāh Abbas I of Persia's Safavid army captures the city of Yerevan from the Ottoman Empire after a siege. At this time the Shāh begins the expulsion of Armenians from Jolfa to New Julfa in his capital of Isfahan; more than 25,000 die during the exodus.

  July–September

• July 4 - The Jesuits Act 1603 is given royal assent by King James I of England to create penalties against Jesuits and Catholics who send their children abroad to Catholic colleges.
• July 7
• *On 11 Safar 1013 AH in the Islamic calendar, the decree of Ottoman Sultan Ahmed I is read aloud in the Great Mosque of Mecca, declaring that Idris ibn Hasan has been proclaimed the new Sharif of Mecca, in partnership with Idris's brother Fuhayd ibn Hasan and Idris and Fuhayd's nephew, Muhsin ibn Husayn
• *King James angrily dismisses the English parliament after failing to get full financial subsidies. He tells the members in his closing speech, "I am not of such a stock as to praise fools."
• July 16 - The last of the 18 sessions of the English and Spanish peace conference is held at the Old Somerset House in London, with the parties reaching an agreement on terms of a treaty.
• July 22 - King James begins fundraising for his project for an accurate translation of the Holy Bible into English, asking Richard Bancroft, Archbishop of Canterbury, to contact all Anglican churches for donations.
• August 5 - Sokolluzade Mehmed Pasha becomes the new Ottoman Grand Vizier, replacing the late Yavuz Ali Pasha
• August 18 - England concludes the Treaty of London with Spain, ending the Anglo-Spanish War, an intermittent conflict within the Eighty Years' War.
• August 19 - The Dutch siege of Sluis in the Spanish Netherlands ends after three months, a day after relief troops commanded by General Ambrogio Spinola retreat. At least 2,000 of the members of the Spanish garrison inside had been killed or incapacitated by disease and famine. Sluis becomes part of the Netherlands afterward.
• September 1 - Sri Guru Granth Sahib, the religious text of Sikhism, whose compilation by Guru Arjan was completed on August 29, is installed at Harmandir Sahib in Amritsar.
• September 20 - After a bloody three-year siege. Ostend is finally captured by Spanish forces under Ambrogio Spinola

  October–December

• October 4 - Za Dengel, Emperor of Ethiopia, is killed in battle with the forces of Za Sellase, who restores his cousin Yaqob to the throne.
• October 9 - Kepler's Supernova is first observed from the northern parts of the Italian Peninsula. Beginning on October 17, Johannes Kepler begins a year's observation of it from Prague. There won't be another supernova visible to the "naked-eye" until 1987., this is the last supernova to be observed in the Milky Way.
• November 1 - The first recorded performance of William Shakespeare's tragedy, Othello, takes place at the Palace of Whitehall in London.
• December 26 - On the evening of Saint Stephen's Day), the first recorded performance of Shakespeare's "problem play" Measure for Measure takes place, before King James I of England in the banquet hall of the Palace of Whitehall.
• December 29 - The 1604 Quanzhou earthquake, with an estimated 8.1 magnitude, shakes the Taiwan Strait leaving several dead.

  Date unknown

• France begins settling Acadia, first successful French North American colony.
• Before 1 October, Huntingdon Beaumont completes the Wollaton Wagonway, built to transport coal from the mines at Strelley to Wollaton just west of Nottingham, England, the world's oldest wagonway with provenance.
• The Table Alphabeticall, the first known English dictionary to be organized by alphabetical ordering, is published.
• First publication of Christopher Marlowe's play The Tragical History of Doctor Faustus, in London.
• Lancelot de Casteau's L'Ouverture de cuisine published in Liège, including the first printed recipe for choux pastry.

  Religion

• According to legend, the vault of Christian Rosenkreuz is discovered.
• The Papacy is expected to fall this year by Tobias Hess and Simon Studion according to their correspondence in 1597.

  Births

January–March

• January 4 - Jakob Balde, German Latinist
• February 2 - Juan de Leyva de la Cerda, conde de Baños, Spanish noble
• February 24 - Arcangela Tarabotti, born Elena Tarabotti, Venetian nun and feminist
• March 10 - Johann Rudolf Glauber, German-Dutch alchemist and chemist
• March 19 - King John IV of Portugal
• March 23 - Girolamo Colonna, Catholic cardinal

  April–June

• April 5 - Charles IV, Duke of Lorraine
• April 9 - Duke Francis Henry of Saxe-Lauenburg
• April 17
• * Giovanni Giacomo Barbelli, Italian painter
• * Frans Luycx, Flemish Baroque painter
• April 22 - Peter Venables, Welsh politician
• April 28 - Joris Jansen Rapelje, Early Dutch settler in colonial North America
• May 1 - Louis, Count of Soissons
• May 4 - Sir Hugh Owen, 1st Baronet, English politician
• May 10 - Jean Mairet, classical French dramatist who wrote both tragedies and comedies
• May 17 - Vincent Baron, French Dominican theologian writer
• May 28 - Catherine of Brandenburg, Princess of Transylvania
• June 4 - Claudia de' Medici
• June 10 - John Manners, 8th Earl of Rutland, English politician when he inherited the peerage
• June 17 - John Maurice, Prince of Nassau-Siegen
• June 28 - Heinrich Albert, German composer and poet
• June 30 - Margaret Elisabeth of Leiningen-Westerburg, Regent of Hesse-Homburg

  July–September

• July 8 - Christiaen van Couwenbergh, Dutch painter
• July 25 - Dorothea Diana of Salm, German noblewoman
• August 4 - François Hédelin, abbé d'Aubignac, French author
• August 12 - Tokugawa Iemitsu, Japanese shōgun
• August 16 - Bernhard of Saxe-Weimar, general in the Thirty Years' War
• August 25 - Shang Kexi, Chinese general
• September 13 - Sir William Brereton, 1st Baronet, English soldier and politician
• September 21 - Angelo Michele Colonna, Italian painter