The convention establishing the International Maritime Organization (originally called the Inter-Governmental Maritime Consultative Organization) was drawn up in 1948 by the UN Maritime Conference in Geneva, but it was 10 years before the convention went into effect. The conference decided that the IMO's success depended on participation by most of the nations with large merchant navies, and it specified that the organization would come into being only when 21 states, including seven having at least 1 million gross tons of shipping each, had become parties to the convention. On 17 March 1958, the convention went into effect. The first IMO Assembly met in London in January 1959. The relationship of the IMO to the UN as a specialized agency was approved by the UN General Assembly on 18 November 1958 and by the IMO Assembly on 13 January 1959.