An indenture (a type of legal contract) under which John Owen (and thereafter his estate) promised to pay an annual sum of £9 12s to the governors of the school on 20 March of each year. William Marsh, another governor of the school, signed the contract with Owen on behalf of the governing body. The £9 12s sum was intended for the 'better maintenance of the Free School [QE], physic well, and poor people of the parish of Chipping Barnet.' Three pounds were paid to the Master of the school to provide free education for 3 poor boys from Barnet, three pounds were directed to repairs of the school buildings, and one pound were directed to repairs of the Barnet physic well or, in certain circumstances, the free education of one other poor boy. The remaining 52 shillings were to provide bread for the poor in Barnet. As late as 1935, the £9 12s was still being paid annually to the governors of the school by the Fishmongers' Company.

The indenture has John Langham's signature in the bottom right corner, under the fold (not visible in photographs). The indenture is dated 1677, yet Langham died in 1671. It is unclear why and how his signature is present on the document. It is possible that the animal membrane writing material was signed by Langham before his death and then repurposed in 1677 when the governors were drawing up the indenture.