Having secured their accession, Sardar Patel and V. P. Menon then proceeded, in a step-by-step process, to secure and extend the central government's authority over these states and to transform their administrations until, by 1956, there was little difference between the territories that had formerly been part of British India and those that had been princely states. Simultaneously, the Government of India, through a combination of diplomatic and economic pressure, acquired control over most of the remaining European colonial exclaves on the subcontinent. Fed up with the protracted and stubborn resistance of the Portuguese government; in 1961 the Indian Army invaded and annexed Portuguese India. These territories, like the princely states, were also integrated into the Republic of India.