Pontage is derived from English custom law in the same way that lordship titles are. It is the toll that is levied for the building or repair of a bridge or bridges.
The reason the lord was held in such high esteem was because they took on the responsibility of looking after their tenants. Whilst generally this was to ensure no one starved, the lord also had to co-ordinate large scale projects as well for the good of the people who lived within the manor.
Like most things in medieval England there was a strong element of control from the Crown. Whilst in pre-Norman times a type of pontage existed this was formalised, like many things, to ensure they happened and the Crown had their fair share. So in post-Conquest England pontage required a grant from the Crown in order for it to be charged. Historic records exist to show that grants were made between 1228 and 1440 for pontage, the practice dying out at that time as the majority of bridges were built to meet the needs of England and maintenance would have to be made from the local economy.
The earliest bridges were at Ferrybridge, Yorkshire and Staines Middlesex. Pontage played a key role in allowing travel and trade to occur across the River Thames. The natural barrier of the river without sufficient bridging would have resulted in two economic centres, and not the one that we know today. In all it is believed that approximately 370 grants of pontage were made.