Late in the spring of 633 CE, Caliph Abu Bakr of the Rashidun Caliphate was pondering the battle plans for the coming Invasion of the Sassanid Empire. The casualties would be massive, and the war would take years to accomplish. Abu Bakr knew this, and he needed a solution.
A few days later, strange travelers in strange clothing approached the Caliph's palace in Medina, accompanied by pounds and pounds of baggage strung on camelback. The travelers told of the planned Sassanid Invasion in detail almost impossible to make up. The travelers said that they had equipment to help shorten the war and minimize the casualties. They also told of how they could train the Caliphate's army how to use them. The travelers then brought out of the bags, some of the most advanced technology the 7th Century world had ever seen. The travelers, over the course of the next few days, bring back even more technology that amaze the Caliphate government. During the next few months preceding the invasion, the travelers teach the soldiers of the Caliphate how to use the technology against the Sassanid Empire.
The Invasion of the Sassanid Empire instead of taking the OTL 11 years, takes but one month. Over the course of the next few decades, civil wars are crushed, nations are conquered, and the Rashidun Caliphate remains the most advanced country on earth for the next millennium.
In 1899, Caliph Ahmad Majid declares the Empire of Ummah, the united empire of Islam. The world is still, as it had been for over one thousand years, is in awe at the empire's power.