The Ilkhanate will attempt to invade many Muslim (and non-Muslim) nations across the Middle East and will usually succeed, starting with Khiva and it will keep going to Mesopotamia (and, in some cases, the Mediterranean coast). Usually with the original version you will get those 121 thousand troops, however, with the new patches, you won't get those courtiers and troops any longer. The Ilkhanate will then come bearing at least 121 thousand troops to invade Persia and will usually be successful with that. For now, the Europeans are safe the Hordes are not coming your way just yet. All will be quiet, however, until May of 1218, at which time you will receive a second message telling you that the Scourge has arrived, and if you examine the Khan's character page, which is accessible from his portrait in the message, you will see that he has invaded Persia (as historically happened when the Persians dismissed the Khan's diplomats, rather against their better judgement).
This is the game's way of telling you that everything you know and love about your insignificant kingdom/empire/duchy will be utterly destroyed, or, more formally, that the Mongols are about to arrive on the scene. In January of the year 1215, you will get a rather ominous message telling you of rumours of a Khan of Khans in the east.
