King Juan Carlos and Queen Sofia were in Romania in recent days to mourn King Michael, who received a state funeral despite not dying as a reigning monarch.
King Juan Carlos and Queen Sofia with other members of European royalty.
King Michael ruled during two different periods of Romanian history before being forced to abdicate. He died earlier this month in Switzerland.
Both King Juan Carlos and Queen Sofia shared family and friendship ties with King Michael.
Marín González was Congress president from 2004 to 2008 under the Socialist Party. He was also a diplomat and helped Spain become a member of the European Union.