October 9, 1731:Ferdinand Nicolaus Dyonisius DEJEAN born in Bonn and baptised (Catholic) the same day in St Remigius Church; his parents are Anton DEJEAN, also
referred to as "Leveillé" (b. 1697/99?), cupbearer (sommelier) of the Prince-Elector of Cologne (Clemens August), and Maria Joseph BOURLON (b. ?), who were married in the same place on
December 17, 1730.
September 14, 1737: His sister Maria Petronilla Auguste Francisca DEJEAN baptised in Bonn.
February 23, 1741: His brother Clemens August Matthias DEJEAN baptised in born (died early probably, between 1743 and 1749). Prince-Elector Clemens August acts as godfather.
1741/45: Probably visited a Latin School at Bonn (Jesuit College in Bonngasse?).
January 6, 1745: Dejean receives the clerical tonsure (first level priesthood)
1745/46: DEJEAN's apprenticeship with the Elector's personal physician Bernhard VELTRUP (1700-1766) probably takes place during these years.
1746/56 (?): 10-year sojourn at Paris and Strasbourg, where DEJEAN visits leading medical and surgical academies (among them the L’Académie royale de Chirurgie in Paris?)
supported by a scholarship donated by the Elector.
January 27, 1752: Burial of his mother at Bonn. His father Anton DEJEAN marries his second wife, Catherina Lambertina DETHIER (born around 1715), on June 24 at Bruhl.
Between 1754 and November 1756: DEJEAN gains employment as first surgeon in the regiment of Baron Wenge, commander of the elector's military in the Bishoprig of
Münster.
Januar 1757: DEJEAN writes to Prince-elector Clemens August to gain support for his plans to set himself up as a doctor at Münster.
1757: DEJEAN's first sojourn at Amsterdam. He is still destitute and attempts in vain to find an employment.
Winter 1757/1758: Second residence at Amsterdam. DEJEAN successfully sits an examination by the "Examinator Chirurgie" of the Dutch East-India Company (VOC).
Batavia & Asia
June 24, 1758: DEJEAN's employment as "Opperchirurgijn" (Senior Surgeon, ship's doctor) aboard the VOC-ship "De Drie Papegayen" begins at Texel.
July 2, 1758: The ship departs for Batavia (today's Jakarta on the isle of Java, Indonesia).
November 14, 1758: Ship arrives at the Dutch Cape Colony (South Africa).
December 3, 1758: Journey to Batavia continues.
February 13, 1759: Arrival at Batavia.
Spring 1759–June 1762: Occupation as ship's surgeon on various VOC-ships serving the company's trade posts in Asia. Visits (among others) Sumatra, Malaysia, India,
Ceylon, and Persia.
January 17, 1761: Burial of his father Anton at Bonn. In all likelihood DEJEAN did not learn of his death up until his return to Europe.
June 8, 1762: Appointment as Surgeon of the City of Batavia.
January 23, 1767: Death of VOC-official Wilhelmus Johannes BUSCHMAN in Batavia, who relocated there from Kharg in the Persian Gulf in May 1766 with his family.
Summer/Autumn 1767: Dejean marries BUSCHMAN'S widow Ann Mary PACK, a native Englishwoman, daughter of Saint George PACK (clerk of the East India Company) and Ann Mary
CROSS. (The marriage was also the probably occasion for a change of religion as DEJEAN might have joined the Reformed Church at that time.)
November 11, 1767: Ferdinand DEJEAN, his wife and stepson Jacobus Wilhelmus BUSCHMAN (b. 1766) depart for Europe aboard the VOC-ship "Ouderamstel".
January 9, 1768: Ship arrives at the Dutch Cape Colony (South Africa).
March 5, 1768: Journey to Europe continues.
May 15, 1768: Birth of his son Georg(e) Ferdinand DEJEAN aboard the "Ouderamstel".
June 11, 1768: The ship arrives at the isle of Texel.
Amsterdam - Leyden
June 19, 1768: George DEJEAN is baptised at the reformed New Wallonian Church at Amsterdam.
December 5, 1768: DEJEAN returned from Asia as a rich man. A first testament by him and his wife is drawn up at Amsterdam.
Winter 1768/1769: Relocation to the university city of Leyden.
April 4, 1769: Ferdinand DEJEAN takes up his course of studies in medicine and chemistry (at the age of 37!). The renowned professor of medicine Hieronymus David GAUB becomes
his teacher and mentor.
November 6, 1769: Initiation of DEJEAN into the freemasonic lodge "La Vertu" of Leyden. (He probably became a freemason already at Batavia.)
February 1772: Death and burial of his stepson Jacobus Wilhelmus BUSCHMAN at Leyden.
April 9, 1772: Baptism of the freed Indonesian house slave of the Dejeans ("Anna Maria van Java, called Canangan") in
Amsterdam.
Summer 1772: Sojourn in Paris, where a commedatory letter by GAUB enables DEJEAN to establish contact with the medical elite and gain work experience at the renowned hospital
Hôtel-Dieu de Paris.
July 2, 1773: DEJEAN gains a doctorate in both medicine and chemistry. His dissertations are published as books in that same year: the chemical dissertation deals with the
analysis of Castile soap (Sapo medicinalis), the medical dissertation concerns the non-operative treatment of eye diseases.
October 9, 1773: Death and burial (Oct 11) of his wife Ann Mary (also: Anna Maria) DEJEAN, née PACK, at Leyden.
Winter 1773/74: Son George DEJEAN is commited to the care of DEJEAN's university friend Theodor Heinrich TEN NOEVER and his wife at Lingen (Emsland).
1774/1776: DEJEAN undertakes several journeys across Europe, to further his his education, befriend and exchange views with numerous natural scientists, whose common
denominator is the enthusiasm for the ideals of the Enlightenbment.
May 30,1775: Ferdinand DEJEAN's second testament at Leyden.
May 1776: DEJEAN participates in schientific experiments of the Académie Royale des sciences in Paris to determine the nature of diamonds and donates a diamond fot this
purpose.
Spring 1777: Sojourn in Aachen, where DEJEAN conducts experiments with the local sulphurous water.
October 1777: DEJEAN visits his native city of Bonn.
Mannheim - The Hague
November 1777–February 1778: DEJEAN stays at the residential city of Mannheim. He visits Johann Martin ROEMER, a friend from Batavia (by now privy councillor to the court of
the Palatinate) and the astronomical observatory.
December 1777: Meeting with Wolfgang Amadeus MOZART at the house of the mutual friend Johann Baptist WENDLING, flutist of the Mannheim court orchestra. DEJEAN engages MOZART
to compose "3 kleine, leichte, und kurze Concertln und ein Paar quattro [Quartette] auf die flötte" (three small, short and easy concerts and a few qurtets for the flute) for him and promises
200 guilders as remuneration.
February 15, 1778: DEJEAN departs for Paris. MOZART has fulfilled only a part of the assignment and subsequently receives only 96 guilders from him.
1778: Sojourn in London, where DEJEAN gets acquainted with Georg FORSTER und Samuel Thomas SÖMMERRING.
Winter 1778/1979 (?): Relocation to The Hague.
May 2, 1780: Third testament (addition) of Ferdinand DEJEAN at The Hague.
Mai/June 1780: Departure on prolonged journeys to Germany, Switzerland, and Italy, for which three to four years are scheduled.
August 25, 1780: George DEJEAN becomes a pupil of the "Hohe Karlsschule", the military academy of the Dukedom of Wurttemberg, at Stuttgart.
1781: Journeys to London and Vienna (May/June).
Autumn 1781–Spring 1782: Journey to Italy, where DEJEAN stops over at Rome (February 1782), Florence (April 1782), Naples, Viterbo and Siena among other places.
October 10, 1782: Dejean participates in a session of the "Königlich Preußische Akademie der Wissenschaften" at Berlin.
November 1782: DEJEAN stays at Kassel, where he visits the Museum Fridericianum on November 11th (and possibly is reunited with his friends FORSTER, curator of the natural
history collection at the museum, and SÖMMERRING, who are teaching natural history respectively anatomy at the Collegium Carolinum there).
December 9, 1782: Burial of DEJEAN's stepmother Catherina Lambertina DEJEAN, born DETHIER, at Bonn (parish of St Martin).
Rheinberg
Between 1782 and 1784: After repeated previous visits Ferdinand DEJEAN moves to Rheinberg (Lower Rhine region of Germany), where he takes up residence with the family of
his sister Maria Petronilla, who is married to Johann Franz GÖBEL (1722-1809), local treasurer to the Elector of Cologne, intermittently mayor of the town, and later
privy councillor. Active participation in cultural activities of the local gentry such as salon music and literary society.
October 3, 1785: DEJEAN witnesses the first manned balloon flight from German ground, undertaken by the French aviation pioneer Jean-Pierre BLANCHARD from Bornheim Heath
near Frankfurt/Main.
1786/1787: Sojourn in Sweden and Denmark.
May 1787: Ferdinand DEJEAN visits Bonn; among others he sees his nephew and godson Ferdinand Anton GÖBEL, who is studying there, and a friend, the privy
councillor Johann Gottfried MASTIAUX. He expresses his joy regarding the advancement of the Enlightenment in Bonn.
Summer/Autumn 1787: Journey to the south of Germany (Mainz, Karlsruhe, Mannheim, Marburg, Ludwigsburg), Switzerland (Basel) and the Alsace (Strasbourg, Colmar).
December 15, 1787: Burial of his sister Maria Petronilla GÖBEL, born DEJEAN, at Rheinberg.
March 11, 1788: George DEJEAN is appointed junior lieutenant in the Wurttemberg Dragoon regiment "Carl Eugen" (in the service of Austria).
Spring/Summer 1788: DEJEAN accopagnies his son George until at least Vienna. The regiment is deployed in the Banat (Hungary/Romania) and will be involved in heavy
fighting in the course of the Russian-Austrian war against the Ottoman Empire by late summer.
Summer 1788: Gout-ridden, DEJEAN stays at Carlsbad in Bohemia to find treatment for his frail health.
1789: DEJEAN sells part of his library and his collections of physical, optical and mechanical instruments to the monastery of Camp (Kamp-Lintfort/Germany) in return for
a life-annuity of 900 guilders.
November 1790: A substantial part of DEJEAN's library is auctioneered at Leyden by "Luzac & van Damme“.
Vienna
Summer/Autumn 1790: Relocation to Vienna; DEJEAN's final address there is "Fürst Parisches Haus Nr. 844 im Jacoben Hof".
1792–1794: DEJEAN publishes his commentary on the oeuvre of his university teacher GAUB ("Commentaria in institutiones pathologiae medicinalis ...") in three parts (four
volumes).
1793: DEJEAN severely suffers from jaundice and is (temporarily?) cured by his friend and colleague Mathias Edler von SALLABA.
October 9, 1793: Fourth and final testament of Ferdinand DEJEAN at Vienna.
1794–1796: Publication of the German language edition of the "Commentaria..." ("Erläuterungen über Gaub's Anfangsgründe der medizinischen Krankheitslehre"). The
translation was provided by the physician and medical historian Christian Gottfried GRUNER from Jena.
February 23 or 24, 1797: Ferdinand DEJEAN dies at Vienna from cirrhosis of the liver, possibly as a result of chronic gout, and is buried there on February 25th at St. Marx
cemetery (where Mozart was also buried in December 1791). His religion is quoted as "protestant".
March 14, 1797: In a letter from Hermannstadt (Sibiu/Romania) his son George Ferdinand DEJEAN, senior lieutenant in the Dragoon regiment No. 3 ("Major 2. Escadron") since
1795, accepts the inheritance as universal heir.
December 1797: George Ferdinand DEJEAN quits the service in the Austrian army.
December 16, 1799: George Ferdinand DEJEAN dies at Vienna (Auf der Wieden) of jaundice and is interred at the catholic Matzleinsdorf cemetery (nowadays Waldmüllerpark) two
days later.
