It was formed by people from the anti-Francoist opposition, like Gregorio Peces-Barba or Joaquín Ruíz-Giménez.

ID was officially constituted in April 1976 at El Escorial, under the leadership of Joaquín Ruiz-Giménez and José Maria Gil-Robles.

Internal differences led to a split, mainly of the more moderate sector led by Fernando Álvarez de Miranda, shortly after the party was founded.

For the 1977 general election, the party was a member of the Federation of Christian Democracy, which was also included into the Christian Democratic Team of the Spanish State.

ID dissolved in 1979 and its members joined other parties, mainly the PSOE and UCD.