The admittance of Latvia, Lithuania and Estonia, Slovakia, Slovenia, Romania and Bulgaria to full membership by 2004, means the borders of the American-European military bloc now extend from the Baltic to the Black Sea.
An upgrade of its weapons and capabilities in line with US demands was also agreed. However, Germany and France led the way in resisting President George Bush's efforts to have NATO agree to military action against Iraq without waiting for UN approval.
There is a lot of historic symbolism surrounding the expansion, with the 19 NATO members holding their two-day meeting in the Czech Republic where just 34 years ago Soviet tanks rolled into the city to bloodily extinguish the Prague Spring.
The then Czech leader Alexander Dubcek's attempts to wrench his country out from under the Soviet yoke were summarily crushed.
Little more than 10 years after the ending of the Cold War which gave rise to the creation of NATO Russia now has the status of associate membership of the western Alliance.
NATO secretary general George Robertson said this was not the end of expansion and he hoped that the former Yugoslavia countries will enter in the future.
Czech President Vaclav Havel, who helped lead his country to independence, welcomed the expansion said. "The era when countries were divided by force into spheres of influence, or when the stronger used to subjugate the weaker, has come to an end."
US President George Bush told the summit: "By welcoming seven members, we will not only add to our military capabilities, we will refresh the spirit of this great democratic alliance; our nation's most important alliance."
But there was a sense that Mr Bush's chief reason for being in Prague was to build support for military action against Iraq. While he ignored NATO's offer of help in Afghanistan which led to NATO deciding to upgrade their operation, the signs are that he will not ask NATO for their help if he decides to act against Iraq.
Washington confirmed they have contacted about 50 countries seeking their support individually and a NATO spokesperson said yesterday that the US was acting unilaterally in this.
Whatever hope Mr Bush had in getting the overall backing of what he described as his most important alliance were dashed when France and Germany flatly refused to support the initial US wording of a statement on Iraq.
Both countries refused to go beyond the wording of the UN resolution and instead confirmed their commitment to "take effective action to assist and support the efforts of the UN to ensure full and immediate compliance by Iraq, without conditions or restrictions, with UN (resolution) SCR 1441. We recall that the Security Council in this resolution has warned Iraq that it will face serious consequences as a result of its continued violation of its obligations."
French President Jacques Chirac who forced the US to compromise on the UN resolution, met President Bush yesterday during the summit. Afterwards Mr Chirac's spokesperson said the two men agreed on the following: "If Iraq does not respect its obligations, this will be reported by inspectors to the Security Council. The council will draw its own conclusions. All options are open. Iraq must seize the opportunity being presented to it and must understand that this is its last chance."
Some believed the Germans, in their efforts to repair the damage done to the US relationship during the general election, would be willing to compromise on tougher wording on Iraq.
However, this was not the case. Neither was there an official meeting between Mr Bush and German Chancellor Gerhard Schroeder. A diplomat described the relationship now as "professional but not personal".
Officials are adamant the new NATO force of 20,000 soldiers on constant alert to be deployed within seven days will not cut across the EU's Rapid Reaction Force of 60,000 soldiers ready within 60 days.
But since NATO will draw from much the same military pool as the EU's force there could be problems.
Partnership for Peace, of which Ireland is a member, meets today with the State represented by European Affairs Minister for State Dick Roche.