[2] On 26 April 1876 on the grassy fields just outside Copenhagen which later became Fælledparken, Markmann co-founded Kjøbenhavns Boldklub (KB), one of the first sports club in the country.

[3][4] Markmann was the chairman of KB between 1880 and 1883, carrying out a great deal of work over the three years and was appointed an honorary member upon his resignation.

[5] This is due to the fact that at the beginning, the primary driving force behind DBU was not football, but cricket.

Although football still had a tarnished reputation, Markmann believed that it was ideal for winter training for the cricketers and therefore had every right to be part of the association.

[5] It was under his presidency, that DBU organized the first edition of Fodboldturneringen (English: The Football Tournament), which was held between 1889 and 1903, with KB winning on four occasions, including back-to-back titles in 1896–97 and 1897–98.