The truth, if ever it emerges, will come too late for Emilia Girón. For 65 years, the hard-bitten mother of seven ached to know what had become of her son, Jesús. Born during the vengeful early years of Franco's rule, he was taken from her to be baptized shortly after his birth. She never saw him again.

The story is part of a dark and overlooked chapter of the repressive Franco era that has drawn new attention since November, when Judge Baltasar Garzón ordered provincial judges to investigate the "disappearance" of children taken from leftist families as part of an effort to purge Franco's Spain of Marxist influence.

Historians and associations that represent Franco's victims assert that hundreds of children were taken from Republican families and adopted or sent to religious schools and state-run homes.

Some were baptized with new names, the historians say, their birth records hidden or destroyed. Others, sent into exile during the war by the Republicans and brought back by Franco, were given new identities.

In a 152-page court order, Garzón wrote: "There was a 'legalized' disappearance of minors, who lost their identity, and whose number remains uncertain." The judge suggested that there could be thousands of "lost children," but historians say there are less.

Ricard Vinyes, a professor of modern history at the University of Barcelona and author of a book on female prisoners of the era, said documents and oral testimonies indicate that hundreds of children lost their identities when they were separated from their imprisoned mothers.

The case was echoed in Argentina's "dirty war" of the 1970s and '80s, in which children of murdered dissidents were stolen and sometimes adopted by military families. Vinyes said Franco was open about his project to "re-educate" the children of his enemies.

Franco's top military psychologist, Antonio Vallejo Nágera, claimed that Spain could be saved from Marxism by isolating children from Republican parents. A 1940 decree allowed the state to take a child into custody if their "moral formation" was at risk.

Catholic schools and the welfare system known as Social Aid became a machine for political reorientation. Social Aid children led a life of fascist doctrine, harsh discipline and Catholic ritual, Cenarro said.

Vinyes said nearly 31,000 children were registered as being in state custody at some point from 1945 to 1954, the majority of them from Republican families.

Now that Garzón has ordered the investigation into "lost children," groups that represent Franco's victims believe they may locate some of them. In January he instructed provincial courts to collect DNA samples from several elderly or sick Spaniards searching for family members.

Fernando Magán, a lawyer for the Association for the Recovery of Historical Memory, said judges could open up adoption registers and lists of children in Social Aid homes and religious schools.

Prada, who settled in France in 1958 but returns each winter to Lombillo, said finding his brother would help close wounds.

"It has left a hole in my life, knowing that I have a brother, not knowing where he is, whether he was brought up by good people," he said, fingering the yellowed Family Book where Jésus should have been registered.