Stilbe
She bore Apollo twin sons , Centaurus , ancestor of the Centaurs , and Lapithus , ancestor of the Lapiths . 
<triplet> Apollo <subj> Centaurus <obj> child <triplet> Centaurus <subj> Apollo <obj> father <subj> Lapithus <obj> sibling <triplet> Lapithus <subj> Apollo <obj> father <subj> Centaurus <obj> sibling