A year ago today, 25 Sandinista gurerrillas shot their way into Nicaragua's National Palace, held more than 1,000 of former president Anastasio Somoza's top lieutenants hostage for two days and then escaped in a military plane sent by Venezuela's then president, Carlos Andres Perez, to fight again.

Today, in an emotional ceremony commemorating the takeover of the National Palace and honoring Perez, Nicaragua's new junta, other leaders and a crowd of about 15,000 celebrated the event that was the beginning of the end of Somoza's dictatorship.

Perez, who supplied the Sandinista guerrillas with financial, diplomatic and, it is commonly believed, military support, gave an emotional speech in which he called the takeover of the National Palace "an audacious act that changed the course of the armed struggle against Somoza -- and with it the course of the country's history."

"The Nicaraguan people felt the heroism and the sacrifice of those Sandinistas who seized the palace," Perez said. He described them as "the vanguard of the revolution" but not its sole proprietor.

In what was clearly a message aimed at the more radical members of the Sandinista front, Perez said, "This revolution is the property of the Nicaraguan people -- of the farmers, the workers, the middle class, the intellectuals, and the Catholic Church, which placed itself on the side of the people."

Among those on the grandstand in front of the National Palace, which today was renamed the Palace of the Revolution, were the guerrilla leaders who seized the building a year ago. The structure, now in disrepair, houses government offices and the old House of Deputies and Senate chambers.

Eden Pastora, who became known throughout the world as Commander Zero, and Dora Maria Tellez, known as Commander Two, stood proudly, surrounded by their fellow Sandinistas in uniform and the new govermnent's military and civilian leadership.

Also on the grandstand was Tomas Borge, one of 59 Sandinista guerrillas freed from jail last year by Somoza as part of the agreement that ended the two-day palace siege. Borge is interior minister in the new government, a commander of the newly formed army and considered the most powerful figure in the country today.

Perez' visit follows those of Rodrigo Carazo Odio, the president of Costa Rica, two weeks ago and Gen. Omar Torrijos, Panama's strongman, last weekend.

The crowds for both of them were substantially larger than for Perez today, a fact attributed to increasing employment in Managua and less public enthusiasm for state visits, demonstrations and pageantry -- which are becoming routine here.