Construction began in July 1979 based on the plans of the architect József Finta and the interior designer László Király.

In 1994 as the second phase of privatization the Forum Hotel went over into ÁPV RT’s ownership (as a state property) in order to prepare its sale.

As of 1 November 1996 InterContinental owned the hotel with 95% after half a year the company bought the remaining 5% of employee shares.

In 1944, the diplomats Carlos de Sampayo Garrido (Ambassador) and Alberto Teixeira Branquinho (Chargé d'affaires) granted entry visas to Portugal to those refugees persecuted and threatened with imprisonment and death by Nazi Germany and its Hungarian allies.

They acted under instructions and with the full backing of the conservative and authoritarian Portuguese regime[2] and their actions made it possible for approximately 1000 Jewish refugees to escape The Holocaust and find in Portugal a gateway to safety and freedom.