He came; he saw; he conquered.

But it wasn't Gaul that Pope John Paul II conquered this week--it was the hearts of the 400,000 Bostonians who turned out Monday to see him on his motorcade route and in Boston Common on a rainy, chilly day.

The Pope, who has focused his visit on youth, told the predominatly young audience that they should concentrate more on following Christ than on trying to escape their problems through violence, sexual gratification or drugs.

Though his homily chided Americans for material and physical excesses, the audience responded warmly to him. interrupting his address 40 times to applaud. Many people in the crowd had waited to see him for six hours.

The Pope found equally receptive audiences in New York, Philadelphia, Des Moines and Chicago this week. In New York, an enthusiastic group of high school students presented the delighted pontiff with a sweatshirt and blue jeans and played basketball marches for him.

In a field in Iowa the Pope addressed 350,000 people, where he reaffirmed that the priesthood requires a traditional life-long commitment. He also said God has chosen only men "to shepherd his flock."

But the Pope's message of love and faith did not reach everyone. The Federal Bureau of Investigation Tuesday received a letter from a terrorist group threatening his life.

And in Boston, 1000 protesters outside Holy Cross Cathedral chanted "stop racism now" and held up placards to attract the Pope's attention. The racially-mixed demonstrators were protesting the shooting of a high school football player last week in Charlestown. The Secret Service rerouted the Pontiff to avoid the protesters.

The state of Massachusetts was ready for any crowd. More than 1000 policemen, with 7000 more security forces in the downtown area guarded a common cordoned off with hundreds of blue barrels and bedecked with banners. Subways ran at rush hour frequency for much of the day, and several thoroughfares were closed

Hucksters were ready for the crowd, too. Though the rain reduced the expected throngs by about half, peddlers were out in full force, and in violation of a two-day ban on hawking downtown. Selling posters, records, flowers, buttons and even "Pope adds Life" t-shirts, they tried to make a buck off sentimental throngs.

The Pope's speeches may not permanently affect Church attendance, however. "It will take a lot more factors than a Pope's visit for people to decide whether to join the Church," Father Francis Rimkus, managing editor of the Pilot--the archdiocese newspaper--said.

The Pope's emphasis on how Christ answers many of the questions of youth may lead Americans to think about the Roman Catholic Church--in which the average attendance at Masses has dropped about 25 per cent over the past decade, Rimkus added.

The Pope has tried over the past year to identify himself with people from every world, through visits to Mexico, Poland and Ireland, George H. Williams, Hollis Professor of Divinity, said this week.

And as one priest from New Hampshire said after he had seen the Pope: "Being of Polish descent myself, I'm proud of the man."