A better class of Sipahis, better suited to hand to hand combat than their archers counterparts.
Sipahis are feudal cavalry, holding land in exchange for military service. In western regions of the Ottoman empire especially, many Sipahis remained Christian. Lancers are drawn from the wealthier Sipahis who can afford the armour needed by close combat soldiers. They make solid cavalry who can ride down poorer quality infantry, while having enough mobility for flanking moves.