JERUSALEM — The fragile treaty between the two former enemies was not even three years old when a Jordanian soldier went on a shooting rampage and killed seven Israeli schoolgirls visiting a park in a border area known as the Island of Peace.

On Sunday, almost 20 years after that March 13, 1997, attack, the Jordanian authorities released the soldier, Ahmed Daqamseh, a former corporal, after he effectively completed his term.

Amid the grief and outrage over what became known as the Island of Peace massacre, King Hussein, then the ruler of Jordan, managed to salvage the spirit of reconciliation and provide some balm.

The king paid a rare visit to Israel and made condolence calls to each of the bereaved families. Kneeling to speak with them as they sat on the floor in their homes as part of the Jewish mourning custom of shiva, he apologized and said: “Your daughter is like my daughter. Your loss is my loss.”