Around 1604 John Critz (age 53) is believed to have contributed to the Somerset House Conference painting of the negotiation of the Treaty of London in which Thomas Sackville 1st Earl Dorset (age 68), Charles Howard 1st Earl Nottingham (age 68), Charles Blount 1st Earl Devonshire (age 41), Henry Howard 1st Earl of Northampton (age 63) and Robert Cecil 1st Earl Salisbury (age 40) are represented on the right side.

On 18 Aug 1604 the Treaty of London was signed concluding the nineteen-year Anglo-Spanish War. The treaty restored the 'Status quo' between the two nations. The negotiations probably took place at Somerset House [Map] in Westminster and are sometimes known as the Somerset House Conference.