Rooke hoisted his flag in the second-rate HMS "Shrewsbury" in Spring 1700 and took command of an Anglo-Dutch Squadron, which while working in co-operation with a Swedish fleet under Admiral-General Hans Wachtmeister, attacked Copenhagen so facilitating the landing of King Charles XII of Sweden and his army in Denmark in August 1700 in the opening phase of the Great Northern War. When the Admiralty was reconstituted under a council headed by the Lord High Admiral (an office vested at that time in the Earl of Pembroke), Rooke was appointed a member of the council of the Lord High Admiral in January 1702. He was also appointed Vice-Admiral of England later that year.