At the age of 92, the historian Nicolas Sanchez-Albornoz is an unlikely graffiti artist. But on Tuesday, 70 years after being sent to a prison labor camp in a wave of repression by Spain’s Franco dictatorship for painting the words “Long Live Free University!” he returned to the scene of the crime for a symbolic reconstruction of the slogan.

“I am moved,” a tearful Sanchez-Albornoz said after receiving tributes from students at Madrid’s Complutense University, where he had been arrested as an undergraduate in 1948 along with 13 other members of the underground University Students’ Federation. He was sentenced to six years’ imprisonment in a work camp on the site of Gen. Francisco Franco’s colossal mausoleum, now known as the Valley of the Fallen.

“When I was at university, we couldn’t imagine seeing an event like this,” Sanchez-Albornoz said before applying the first slosh of black paint to the symbolic reconstruction on the wall of the political science and sociology building.

The event was held on a notorious date in Spain — Nov. 20 — when groups of Franco sympathizers mark the anniversary of the deaths of the dictator, in 1975, and that of José Antonio Primo de Rivera, founder of the fascist Falange party, who was executed by Republican forces in 1936, the first year of the civil war that led to a four-decade dictatorship. According to the Francisco Franco Foundation, 16 churches around Spain were holding special Mass services for the dictator on Tuesday. At the Valley of the Fallen basilica 30 miles northwest of Madrid, several hundred fascist supporters joined in prayer, some offering stiff-arm salutes over the military ruler’s tomb. ...