The date of the birth of Aaron is usually given to be around 1125 (although other sources show it to be between 1123 and 1130). Aaron died in 1186. He was born in Lincoln but spent some of his early life in France. He owned a plot of land near to Lincoln Castle and his original house was likely situated on this land before it was demolished to make way for castle defence extensions in 1227-28. It is believed that he was the wealthiest man in Norman England.

Aaron first appears in official government records, called a pipe-roll, in 1166, and records show that King Henry II owed him a large sum of money. In fact, Aaron’s business operations spanned commodities, property, and funding great architectural projects such as lending money especially for the building of important religious places, such as abbeys, cathedrals and monasteries, and castles too. Some places he helped fund at various stages were the Abbey of St Albans, Lincoln Cathedral, Peterborough Abbey and no fewer than nine Cistercian abbeys. He also lent money for land, and for things like corn, armour and houses as security. This resulted in him having a keen and varied interest and impact in many areas all over eastern and southern England.

When Aaron died in 1186, many of his loans remained outstanding. By law the money passed to Henry II and Henry seized his property and the English crown thus became universal heir to his estate. But with Aaron’s affairs so extensive and on an unprecedented scale, it took a dedicated department of England’s Exchequer (known as Aaron’s Exchequer) to specifically manage, track, and collect the massive estate left By Aaron of Lincoln. This continued until at least 1201, fifteen years after his death. The actual cash treasure accumulated by Aaron was sent over to France to assist Henry in his war with Philip Augustus, but the vessel containing it went down on the voyage between Shoreham and Dieppe.

A house sometimes associated with Aaron Of Lincoln still stands, also known as the Norman House (numbers 46-47 Steep Hill). This building dates from the 12th century and is a Grade 1 listed building. This was often incorrectly known as the house of Aaron of Lincoln.