After the murder of his former friend and later opponent Thomas Becket, Archbishop of Canterbury, the penitent King Henry II commissioned a new stone bridge in place of the old, with a chapel at its centre dedicated to Becket as martyr. The archbishop had been a native Londoner and a popular figure. The Chapel of St Thomas on the Bridge became the official start of pilgrimage to his Canterbury shrine; it was grander than some town parish churches, and had an additional river-level entrance for fishermen and ferrymen. Building work began in 1176, supervised by Peter of Colechurch. The costs would have been enormous; Henry's attempt to meet them with taxes on wool and sheepskins probably gave rise to a later legend that London Bridge was built on wool packs. After Colechurch's death, Isembert, a French monk who was renowned as a bridge builder, was appointed by King John to complete the project. Construction was not finished until 1209 during the reign of King John. John tried to recoup the cost of building and maintenance by licensing out building plots on the bridge but this was never enough. In 1284, in exchange for loans to Edward I, the City of London acquired the charter for the maintenance of the bridge, based on the duties and toll-rights of the former "Brethren of the Bridge".