Written of course before Europeans descended into warlike savagery the likes of which no Mohammedan culture has ever surpassed
Try harder. I suggest the Mongols. Timur being one example.
In 1383 Timur started the military conquest of Persia. He captured Herat, Khorasan and all eastern Persia by 1385 and captured almost all of Persia by 1387. These conquests were characterised by exceptional brutality. For example, when Isfahan surrendered to Timur in 1387, he initially treated it with relative mercy as he commonly did with cities that surrendered without resistance. However, after the city revolted against Timur's punitive taxes by killing the tax collectors and some of Timur's soldiers, Timur ordered the complete massacre of the city, killing a reported 70,000 citizens. An eye-witness counted more than 28 towers, each constructed of about 1,500 heads.
There were plenty of historical instances when these basically nomadic Islamic tribes massacred whole cities in South Asia and China.
As Dr. North says, they just aren't that organised recently to do as much damage, presumably because nomads have been marginalised by the power of large urban states.
Terrorism like assassination can be thought of as an extension of the nomadic raiding psyche - Al Qaeda just have political rather than wealth booty in mind.
Still there is some modern organisation - the Ottomans managed the Armenian genocide and the ethnic-cleansing of Greeks from Asia minor.
The North Africans the Barbary slave raids, the Arabs slavery from Sub-Saharan Africa.
More recently we were entertained with 8 year olds running in front of tanks as human minesweepers during the Iran-Iraq war which killed about a million, although this might not have gone on so long if we hadn't armed both sides.