Cuban President Raul Castro says he will not seek another five year term after the one he's starting Sunday ends.
He has tapped 52-year-old Miguel Diaz-Canel as his top deputy, ready to assume the presidency without any disruption.
Castro says the country has reached a "transcendent" moment in which it is ready to start transferring responsibility and power to a younger generation.
Diaz-Canel's appointments marks the first time someone who did not directly participate in the 1959 Cuban revolution assumed such an important role.
Castro spoke Sunday evening before parliament.Raul Castro turns 82 this year and would be 86 when a new term ends.
"This National Assembly is important because it formally is going to govern the fate of the country for the next five years, which will be decisive for changing personnel — what I call the intergenerational transition," said Arturo Lopez-Levy, a Cuban economist and analyst who lectures at the University of Denver. "The intergenerational transition cannot be put off any longer."
The 612 legislators were sworn in during the morning and then picked economist Esteban Lazo as the National Assembly's first new chief in 20 years.
Lazo, who turns 69 on Tuesday, is a vice president and member of the Communist Party's ruling political bureau. Parliament meets only twice a year and generally passes legislation unanimously without visible debate.
Ricardo Alarcon, who had been the body's president for two decades, was not on the ballot this year.
The assembly will also nominate the Council of State, Cuba's maximum governing body, which is made up of the president, a first vice president, five vice-presidents, a secretary and 23 other members.
The president also oversees the Council of Ministers, or Cabinet.
Castro has spoken in the past of implementing two-term limits for public officials up to and including the president, as well as the importance of grooming new leaders to take over from his graying generation.
"Raul Castro has said they're behind. He has set the task of promoting people from the younger generation into the leadership, but so far hasn't put them into the top-level leadership," said Philip Peters, a longtime Cuba analyst at the Virginia-based Lexington Institute think tank. "So we will see on Sunday if this is what they do."
President Castro is about halfway through a program of key social and economic reforms that have already seen the expansion of private business activity, legalized home and car sales, an easing of restrictions on foreign travel and the handover of fallow state land to independent farmers.
Cuban state media said both Castros received a standing ovation when they arrived at a Havana convention center for Sunday's parliamentary gathering.
The brothers sat next to each other at the assembly, along with first vice president Jose Ramon Machado Ventura.
Foreign media were not invited to the early parts of the gathering, but were promised access to its closing moments.