Life is a balance between holding on and letting go. After seven years of hostility, Iran and Saudi Arabia have put aside their differences to reestablish diplomatic relations. We add it to the list of what’s right with the world.

Nobody remembers that Saudi Arabia and Iran were once friends and allies. They established diplomatic relations in 1929 with the signing of a Saudi-Iranian friendship treaty. But there was not much cooperation until some decades later.

King Faisal of Saudi Arabia visited Iran in 1966 to strengthen ties. Iran’s Shah Pahlavi responded by paying an official visit to Saudi Arabia and assisting King Faisal in promoting Islamic solidarity. Both countries felt threatened by the spread of Soviet-sponsored pan-Arab nationalism under Egypt’s Gamal Abdel Nasser.

After Israel defeated the Arab states, Egypt, Jordan and Syria in the Six-Day War in 1967, the foundation of Arab nationalism was fatally undermined. Iran and Saudi Arabia took the primary responsibility for security in the region once the British announced that they were going to withdraw from the Persian Gulf.

In the late sixties the Shah sent a series of letters to King Faisal. “Please, my brother, modernize,” he wrote. “Open up your country. Make the schools mixed women and men. Let women wear miniskirts. Have discos. Be modern. Otherwise I cannot guarantee you will stay on your throne.”

King Faisal wrote in reply, “You