1878 | appointment Muziekschool Maatschappij tot bevordering der Toonkunst |
| first Soirée for Chamber Music in Felix Meritis |
1879 | engagement to Amanda Maier |
1880 | marriage to Amanda Maier in Landskrona (Sweden) |
1881 | birth first son, Julius |
| first performance with Johannes Messchaert |
1883 | plays Brahms' Second piano concerto in Amsterdam |
December 1883 | first visit Grieg to The Netherlands, start of a long friendship |
1884-1886 | conductor vocal society Excelsior |
1884 | co-founder Amsterdam Conservatory |
1886 | birth second son, Engelbert |
1886-1888 | managing director Felix Meritis |
1886-1898 | conductor Toonkunst Amsterdam |
1888 | - 11 April: inauguration Concertgebouw |
| - 14 April: last concert Felix Meritis conducted by Julius Röntgen |
| - 21 April: First concert with Toonkunst in Concertgebouw: |
| Beethovens Missa Solemnis |
juli 1884 | first visit to Norway |
1889 | start of long series song recitals with Johannes Messchaert |
1891 | - 25 April: conducts Bach's St. Matthew Passion |
| - 19 December: conducts first performance in Holland of Bach's Hohe Messe |
| - August: travels to Norway; meeting with Grieg and Frants Beyer |
Summer 1892 | first sojourn at Fuglsang |
1894 | Amanda Maier dies |
1895 | Mengelberg conductor Concertgebouw Orchestra |
1897 | - Grieg conducts Concertgebouw Orchestra |
| - second marriage to Abrahamine des Amorie van der Hoeven |
| - Grieg visits Röntgen |
1898 | - first international tour Concertgebouw Orchestra, Music Fest Bergen, by invitation of Grieg |
1898 | - resigns as conductor Toonkunst |
| - birth third son, Johannes |
1899 | - birth daughter Amanda |
1900 | - move to the Van Eeghenstraat |
1900-1914 | - international concert trips, with Messchaert, Casals, Flesch, etc. |
1902 | - First Dutch Music Fest, with performances of works by Julius Röntgen |
| - birth fourth son, Edvard Frants |
| - first meeting with Pablo Casals |
| - performs Beethovens's Fourth piano concerto in Vienna |
1903 | - conducts Concertgebouw Orchestra with own works, in celebration of 25th anniversary in Amsterdam |
1904 | - birth fifth son, Frants Edvard |
| - death Amanda Röntgen |
Summer 1904 | - Fuglsang, start friendship with Carl Nielsen |
1906 | - birth sixth son, Joachim |
| - Grieg visits Röntgen |
| - first Flesch-Röntgen evening Kleine Zaal Concertgebouw |
1907 | - concerts with Grieg in Oslo |
| - concerts with Casals in Paris |
| - last visit to Grieg in Troldhaugen, with Percy Grainger |
| - death Grieg |
| - management musical inheritance Grieg |
1910 | - first concert Percy Grainger in Amsterdam, at instigation of Röntgen |
1911 | - conducts Third symphony in Concertgebouw |
| - conducts Second cello concerto Concertgebouw, with Casals as soloist |
1912 | - Second Dutch Music Fest with performances of work by Röntgen |
| - Carl Nielsen conducts his Third Symphony at the Concertgebouw, at instigation of Röntgen |
1912-1918 | - regular performances with Röntgen Trio (with both eldest sons) |
1913-1924 | - managing director Amsterdam Conservatory |
1913 | - opera 'Agnete', Netherlands Opera Society |
1917 | - attends to edition correspondence Brahms-Engelmann |
1918 | - meets Kees Boeke |
1919 | - assumes Dutch nationality |
from 1921 onwards | - samenwerking met D. van der Ven: vier folkloristiche films met muziek van Röntgen |
1922 | - 22 August: Last meeting with Messchaert |
| - 10 september: death Messchaert |