In a potentially pivotal development, Saudi Arabia and Iran reached a provisional agreement to resume diplomatic ties on Friday.

The regional rivals broke off relations in 2016 after Riyadh’s ill-advised decision to execute Nimr al-Nimr, a Shiite cleric whose death touched off a firestorm (figuratively and literally), pushing the countries to the brink of war.

On-again, off-again talks in Baghdad aimed at smoothing things over bore little fruit, but apparently, venue matters. The tentative truce was struck in China.

“After several days of intensive negotiations in Beijing, an agreement was reached aimed at resuming relations between the two countries,” IRNA said, adding that Riyadh and Tehran will hold additional talks and “make the necessary arrangements for the exchange of ambassadors.”

Last month, I wrote that China’s Middle East pivot was “becoming hard to ignore.” Iran was impatient with what Ebrahim Raisi described as a “serious regression” in the two countries’ bilateral relationship. Ahead of a meeting with Xi in Beijing, he (Raisi) expressed Iran’s desire to speed up the implementation of a strategic plan agreed in 2020.

Read more: China’s Middle East Pivot Is Hard To Ignore

Raisi’s February visit to Beijing came two months after Xi’s highly publicized trip to a GCC summit, where he was treated like royalty by… well, by royalty.

Mohammed Bin Salman is keen to facilitate a good rapport with Xi, and part and parcel of the “petroyaun” narrative is the invoicing of Saudi crude in renminbi.

I’ve repeatedly argued that the sectarian divide is an obstacle to China-Saudi ties and thereby to the petroyuan story (which is far-fetched for a number of other reasons). Riyadh’s relationship with Washington is predicated on security guarantees that Beijing can’t provide given that the Kingdom’s security concerns relate almost solely to Tehran.

That’s the context for news that Beijing has succeeded in brokering the restoration of diplomatic ties between the Sunni and Shiite powerhouses. It’s a geopolitical coup for Xi.

In the same Friday announcement, IRNA said Iran, Saudi Arabia and China “declare their firm will to utilize all efforts to strengthen regional and international peace and security.”

The Saudis released a statement of their own. “The three countries announce that the Kingdom of Saudi Arabia and the Islamic Republic of Iran have reached an agreement that includes resuming diplomatic relations, reopening their embassies and affirming respect for the sovereignty of countries and non-interference in internal affairs,” SPA said.

Riyadh said the Saudis’ engagement was “in response to the generous initiative of His Excellency President Xi Jinping,” who apparently went out of his way “to support and develop good, neighborly relations” between the Kingdom and Iran.