On the 15th June the king, who was then on his way to the coast, took solemn leave of the civic authorities, who had accompanied him to Blackheath. He bade them go home and keep well his "chamber" during his absence abroad, giving them his blessing and saying "Cryste save London."(767) Arriving at Southampton, he there discovered a conspiracy to place the young Earl of March, the legitimate heir of Edward III, on the throne, as soon as he himself should have set sail. The traitors were seized and executed, and the City lost no time in sending the king a letter congratulating him upon his discovery of the plot.(768) (M406) A few days later (12th August) he sailed for France and landed near Harfleur, to which town he laid siege. It offered, however, a stubborn defence, and it was not until the 18th September that the town surrendered. On the 22nd Henry sent a long account of the siege and capture to the mayor and citizens of London, bidding them render humble thanks to Almighty God for this mercy, and expressing a hope of further success in the near future.(769) (M407) (M408) Early in October the king caused proclamation to be made in the City, that all and singular knights, esquires and valets who were willing to go with him to Normandy, should present themselves to his uncle Henry, Bishop of Winchester and Treasurer of England, who would pay them their wages. By the same proclamation merchants, victuallers and handicraft-men were invited to take up their residence in the recently captured town of Harfleur, where houses would be assigned to them, and where they should enjoy the same privileges and franchises to which they had always been accustomed.(770) (M409) (M410)