| . | Year | . |
| 1799 | . |  Alexander
Skakel (1776–1846) establishes a school in Quebec City. |
| 1800 | . | Skakel moves to Montreal and establishes the Classical and Mathematical School. This was the principal educational institution for the. English-speaking population. |
| 1818 | . | Skakel's school is absorbed into the Royal Grammar School in 1818, and he remained as Principal until his death. |
| 1821 | . | Royal Institution for the Advancement of Learning applies to establish public schools in Montreal and Quebec City called Royal Grammar Schools. |
| 1822 | . | The Royal Grammar School founded in Montreal. Alexander Skakel, principal. |
| 1836 | . | Royal Grammar School of Quebec ceases operation. |
| 1842 | . | Prospectus of The High School of Montreal issued |
| 1843 | 0 | September. The High School of Montreal opens with Rev. George F. Simpson as its first Rector. |
|
|
2 | Charter granted The High School of Montreal by the Legislature |
| 1846 | 3 | Royal Grammar School of Montreal absorbed by The High School of Montreal |
| 1852 | 9 |  Financial
difficulties and need for new facilities. Faculty of Arts
and the High School housed in new building called Burnside Hall
at Dorchester and University Streets. School officially adopted as ‘the
High
School Department of McGill College’. |
| 1853 | . | . |
| 1857 | . |
 |
| 1862 |
|
Bookplate presented to James Perrigo showing High School Department of McGill College. |
| 1869 | 23 | Burnside Hall transferred to the Protestant Board of School Commissioners |
| 1874 | . | The High School for Girls founded. Lady Principal and four teachers, trained at the McGill Normal School, appointed. |
| 1892 |
|
 |
| 1965 | . | The High School of Montreal becomes co-educational, absorbs The High School for Girls. Last Lady Principal of The High School for Girls, Dr. Dorothy J. Ross, retires. |
| . | . |
|
| . | . | . |
| 1998 | 155 | School boards divide along language rather than religious lines: Building at 3449 University Street transferred to French school board. |
