BUDAPEST — Péter Magyar will take his oath of office as Hungary's prime minister on Saturday in the neo-Gothic parliament building in Budapest. Thousands are expected to gather outside the parliament square to mark the final moments of Viktor Orbán's 16-year rule.

The center-right Tisza party defeated the nationalist-populist Fidesz party in a landslide victory last month, gaining more votes and seats in parliament than any other party in Hungary's post-Communist history. Nearly 3.4 million Hungarians voted for Tisza in the election.

Magyar, a 45-year-old lawyer who formed the Tisza party in 2024 after years as an insider within Orbán's party, called on Hungarians to an all-day celebration on Saturday to mark his inauguration and the end of the Orbán era. "We will step through the gateway of regime change with a huge party. Come along, and invite your family and friends!" Magyar said.

Magyar is set to address the crowd outside parliament after taking his oath of office around 3 p.m. local time on Saturday. He promised artistic performances and surprise guests for the inauguration event. Tisza officials say they will fly the European Union flag on the façade of the parliament building beginning on Saturday, after it was removed in 2014.

Magyar has vowed to do away with official corruption, which he argues has robbed Hungarians of economic opportunity. The Hungarian economy has stagnated for the last four years. One of his priorities is unlocking about 17 billion euros of EU funds for Hungary that were frozen during Orbán's time in office over rule-of-law and corruption concerns. He has also promised to repair Hungary's ties with its EU partners and to restore the country's place among Western democracies that had come under question as Orbán drifted closer to Russia.

Magyar plans to form the National Asset Recovery and Protection Office to investigate and seek recovery of public funds misused during Orbán's tenure. Many of Orbán's allies and family members were enriched economically during his time in office. He has also vowed to suspend the news services of Hungary's public broadcaster until objectivity can be restored.

The Tisza party is expected to overhaul much of Hungary's governmental structure and create separate ministries for health, environmental protection and education that did not exist under Orbán. Magyar has nominated Anita Orbán for minister of foreign affairs, István Kapitány for minister of economy and energy, and András Kármán for minister of finance.

Gergely Karácsony, the liberal mayor of Budapest, announced a separate party along the Danube River to show gratitude to Hungarians who spoke out against Orbán's system. "Teachers fired, civilians and journalists humiliated, small churches torn apart," Karácsony said. "We can finally leave this era behind us — but first, let us remember the everyday heroes and express our gratitude with a farewell to the system."