of 1940, although he was not a member of the National Socialist Movement in the Netherlands (NSB). During his period as mayor, he was involved in the reconstruction of the centre of Rotterdam which was destroyed by the German bombings. He was heavily criticised by Dutch politicians for cooperating too much with the NSB, while the NSB criticised him for being uncooperative. In the spring of 1941 he was brutally harassed by members of the NSB, twelve party-members invaded the City Hall, gagged Oud, adorned him with Freemason-like symbols and made pictures of him. In the autumn of 1941 he resigned as mayor and he stood down as member of the States Provincial. He was succeeded by Frederik Ernst Müller. In the summer of 1942 he was briefly held in Sint-Michielsgestel, where many prominent Dutch politicians were held captive. During the war Oud kept far from the resistance movement and instead committed himself to writing several books on parliamentary history. Meanwhile, he kept close contact with important people from the business and the political world of Rotterdam. In 1945, after the liberation of the Netherlands, he returned to Rotterdam as mayor, although he was also asked to become mayor of Amsterdam, and he was officially re-appointed in 1946. In the same year the VDB merged with the social democratic SDAP and the left-wing Christian CDU to form the Labour Party. Oud was one of the co-founders of this party and served on the party's board between 1946 and 1947. Meanwhile, he served on many government, business, international and civil society committees, he chaired the government committee for municipal finances between 1946 and 1954, he was member of the board of trustees of the banker Staal, he was member of the pension council of the Dutch Reformed Church since 1946 and he served as chair of the International Union of Municipalities and Local Governments between 1948 and 1954. For the VVD On 3 October 1947, Oud sent a letter to the board of the PvdA announcing his resignation as a member. The reason he gave for the split was that the PvdA was moving too much into socialist waters, instead of being committed to progressive politics. The fact that he was refused a position on the party list for the Senate is generally seen as the political reason for Oud's split. Oud never felt at home in the new social democratic