A mid one of the grandest grand opening celebrations in Cambridge history, the $75 million, 4-2 acre Charles Square complex opened its doors over the weekend to crowds of curious visitors

The long awaited opening comes after nearly seven years of legal and political battles and 19 months of construction, But as bards played and balloons fluttered in the gusty wind, the project's turbulent beginnings seemed far behind it.

Overlooking the Charles River and adjacent to the Kennedy School, the airy brick and glass development includes a luxury hotel, 36 condominiums, a seven story office building, and a spacious plaza of specialty shops.

Built on the former site of the Massachusetts Bay Transit Authority's bus barns--the site once designated for the John F. Kennedy presidential library--Charles Square is the largest mixed-use development in New England.

Chief developer Richard L Friedman of Carpenter and Co. said the complex will add more than 500 jobs and $1.5 million tax dollars to the Cambridge economy

The development's sponsors spent more than $100,000 on the weekend long inaugural festivities, which were highlighted by black-tie parties, a parade, and street performance that continued through yesterday afternoon

House Speaker Thomas P. O'Neill Jr and Gov Michael S. Dukakis joined other local dignitaries for Saturday morning's ribbon cutting ceremony.

This project enhances the value of our area it is something that was long needed in this great city of culture." O'Neill told the hundreds who turned out despite the blustery weather.

Dukakis said the Charles Square complex provided an economic boost for the city. The governor, who also offers a course at the Kennedy School, kept his remarks brief. "I'm supposed to be teaching a class right now at that institution I better get over there or the dean will fire me," he said.

O'Neill and Dukakis took the newly completed subway extension to Harvard Square after cutting another . The two the opening of the Alewife MBIA Station in North Cambridge.

The Alewife Station began service Saturday, marking the end of the 3 2. mile, $574 million Red Line extension that has been under construction for the past seven years.

"The real unsung heroes were the neighbors who had been under a state of stage since the disruption began." Said Cambridge Mavor Leonard J Russell.

Like the Charles Square development, the Red Line extension was undertaken after years of often-bitter disputes involving area residents and state and federal lawmakers.

Fifty years ago, as a freshman representative on Beacon Hill. O'Neill introduced the original bill requesting funds for the subway extension. That steering failed, but O' Neil continued to play an instrumental role in steering key bills through Congress.

The Speaker, who is stepping down from his House next year, greeted dozens of friends and well wishers as he watched Saturday's parade through the Square.