Lud was a legendary king of the Britons as accounted by Geoffrey of Monmouth. He was the eldest son of King Heli and the brother of Cassivelaunus. He is derived from the Welsh hero Lludd Llaw Eraint.

He became king upon his father's death around 73 BCE. During his reign, he became famous for building and repairing towns throughout the kingdom. Most important of these was Trinovantum where he built massive towers all around the city. He built up the homes of the peasantry into lavish buildings comparable to the greatest homes in the world. He arranged massive feasts for the people and greatly enjoyed the city of Trinovantum. It is because of this that it was renamed Kaerlud, 'City of Lud' in Welsh. That named became corrupted into Kaerlundein until the Romans called it Londinium which formed the basis for its current name, London.

He had two sons, Androgeus and Tenvantius, neither of whom succeeded him directly. Lud died and was buried in Trinovantum near a gateway named Ludgate (Porthlud in Welsh). He was succeeded by his brother Cassivelaunus, who acted as regent for Androgeus.

Islamic eschatology

King Lud was suposed to have founded the settlement or City of London. St Paul's Cathedral is situated on top of Ludgate Hill in London, the original settlement of Lud. Below it is the Roman "gate of Lud" called Ludgate.

This is significant for Muslims as Baab-ul-Lud or "Gate of Lud" is where Isa (the Second Coming of Jesus) will confront the Antichrist or 'Dajjal' and defeat him.