Lech Walesa, the irrepressible trade union leader whose Solidarity movement routed communism and sparked democratic change across Eastern Europe, was sworn in Saturday as the first popularly elected president in the thousand-year history of Poland.

"The evil period is ending when the authorities of our state were chosen under foreign pressure," said the 47-year-old vocational school graduate, former shipyard electrician and Nobel Peace Prize winner. "Today we are making a fundamental step on the long and bloody road to rebuilding our independence."Outgoing Prime Minister Tadeuzc Mazowiecki staged a walkout at a symbolic moment during Saturday's event, a sign that tensions remain after a bruising presidential campaign.

In front of both houses of the Polish parliament, Walesa declared that his presidency symbolizes the beginning of a new republic and a definitive break with the Communist past.

Making that point as resonantly as the new president's words was the absence from parliament of outgoing president Wojciech Jaruzelski, the former Communist general who temporarily muzzled the Solidarity movement in 1981 by ordering marital law. He jailed Walesa for 11 months.

Jaruzelski, who served as president for 15 months under a power-sharing deal between Solidarity and the now-defunct Communist Party, was not invited to the swearing-in ceremony. He stayed home and watched it on television.

Walesa addressed the Polish nation as a grayer and notably stouter version of the firebrand with the walrus mustaches who a decade ago molded Solidarity into a national force and an international cause.

But at noon Saturday, his carefully trimmed moustache and dark blue suit notwithstanding, he sounded like the Walesa of old, punching out a 10-minute speech in his trademark, machine-gun staccato.

"I come from a peasant family, and I have been a worker for many years. I shall never forget where I came from on the way that led me to the highest office in the state."

He promised to run a decentralized government that would allow "as many decisions as possible at the grass-roots level, where people live and know their problems."

As he often does, Walesa mixed salt with his populist sugar. He warned the average Pole to wake up, saying that the biggest obstacles to revitalizing the country are "passivity and apathy."

The new president was elected Dec. 9 after a bruising campaign that split the Solidarity movement, fracturing the unique alliance it formed between intellectuals and workers.