Pakistan’s military-to-military cooperation with Saudi Arabia goes back five decades. Between the 1960s and 1980s, tens of thousands of Pakistani troops were stationed in Saudi Arabia, working under Saudi command. Pakistani fighter pilots trained their first Saudi counterparts, and in 1969 flew jets that successfully repulsed incursions by Yemeni forces. Pakistani engineers built Saudi fortifications along its border with Yemen, meant to keep out Shiite Houthi fighters to the south.