HAVANA — Raul Castro, who has labored in the shadow of his brother Fidel since the days of their revolution, became Cuba's new president on Sunday, ending his brother's 49-year rule and washing away hopes on this Communist island that a younger generation might take power.

In his first words as president, Castro made it clear that he would make no radical changes and promised to consult his brother on every important decision. He said his brother was still alive and alert, and the time had yet to come when the leaders of the revolution in the 1950s had to pass the baton to a new generation.

"Fidel is Fidel, you know that well," he said to the National Assembly shortly after it voted him president. "He is irreplaceable, and the people will continue his work even though he is not physically here."

Yet the moment marked a turning point in Cuban history. For the first time since Fidel Castro seized power in January 1959, the government is in the hands of a different leader, a pragmatic military officer who lacks his charisma and ego. Raul Castro has a reputation as a consensus builder, a man who listens closely to his advisers, delegates authority and holds his underlings accountable for their decisions.

The trappings of Cuban leadership had also changed, even if the message did not. Fidel, ever the revolutionary, usually appeared in olive green fatigues; Raul, 76, addressed the assembly in a dark gray suit, a steel-colored tie and gold-rimmed glasses. Raul spoke calmly for half an hour, a sharp contrast with his brother's fiery lectures that frequently rambled on for hours.

Raul Castro also said the government needed to change to survive in the new era. He proposed putting more power in the hands of provincial governments and streamlining the bureaucracy in Havana. "Today a more compact structure is required," he said.

He made it clear no government institution was sacred. "We should never believe that what we have done is perfect," he said.

Despite these hints of change, other actions by the assembly ensured the continued power of Cuba's old guard. It picked another veteran of the revolution, Jose Ramon Machado Ventura, 76, as the first vice president. A former health minister, Machado Ventura has a reputation as a Communist hard-liner fiercely loyal to the Castros.

The assembly re-elected Ricardo Alarcon, 70, as its president.

The decisions seemed to dash the hopes of Fidel Castro's younger followers. Some had expected a younger politician would take over the helm of the legislature, an important bully pulpit even if the body itself only rubber-stamps the president's decisions.