The 1798 Posse Comitatus, a military census, resulted from concerns of a French invasion arising from the Revolutionary Wars (1793-1802) and the Napoleonic Wars (1803-1815). This census included able-bodied men between the ages of 15 and 60 who were not Quakers, clergymen or already serving in a military unit. In addition, the number of horses, wagons and carts were surveyed.

The first such survey appears to have been conducted in Dorset in 1797. The publicity that followed caused several other counties to conduct similar surveys. It was at the initiative of the Lord Lieutenant, the Marquess of Buckingham, that the Buckinghamshire survey was conducted. The work was directed by the High Sheriff, John Penn. He issued instructions on 16 February 1798 and returns were due back by 5 March.

Buckinghamshire is the only county for which a complete copy of the Posse Comitatus exists. There are two surviving copies; one is in the British Library and the other is in the Buckinghamshire Record Office.

The first table records the names of Olney men in the Posse Comitatus. The names are listed under their occupations in four columns. The table provides a valuable insight into the various trades practised in Olney in the late eighteenth century.

The second table lists the availability in Olney of horses, wagons and carts, together with the names of the owners.

The data was kindly provided by Sue Blake.