Via Hsozkult, we learned of a call for papers for a conference on the Schengen System in a historical perspective.
“In 1985, a group of five member states of the European Community (EC), i.e. France, the Federal Republic of Germany and the Benelux countries, signed an agreement in Schengen, whose aim was to remove internal border controls. It also provided for measures to strengthen external border controls and to ramp up the fight against drug trafficking, international crime and illegal immigration. This document, however, was more a working programme than a detailed plan of action and it was outside the community framework. After the Schengen Agreement had been signed, negotiations were therefore opened to decide upon a convention implementing it (CISA). The CISA, signed in 1990 in the wake of the fall of the Berlin Wall, specified the measures, which were to compensate for the abolition of internal border controls; it also established the Schengen Information System, to support external border control and law enforcement cooperation in the Schengen states.” […]
More info here