Around 1786 Adam Gerard Mappa became the commander of a flying army unit, consisting of 300 men and 200 horses, that played a role in democratizing the vroedschap of Utrecht.

[3] From the end of August 1787 under his leadership, the flying army was involved in removing all the Orangists from the vroedschaps in Delft, Gorkum, Montfoort and Vlaardingen.

[7] On the eve of a condemnation, Antje Mappa-Paspoort (a great friend of Emilie Luzac), travelled hurriedly and secretly to Delft, when her husband decided to emigrate to the US, and it is said on the advice of Thomas Jefferson he took his type foundry with him.

His best friend François Adriaan van der Kemp, whom Mappa once called a hermit,[9] came to live in the town's surroundings on a farm.

[11] Mappa corresponded with Pieter Vreede and Johan Luzac and at the end of his life he hit financial difficulties, not being able the pay his debts to the Holland Land Company.