A lithographic method includes patterning a beam of radiation with a patterning device. The patterning device includes at least two image patterning portions and at least two metrology mark patterning portions. The method also includes projecting at least two image portions of the patterned beam of radiation sequentially onto target portions of a substrate such that the projected image portions are substantially adjacent to each other on the substrate and collectively form a composite image on the substrate. The method also includes projecting a metrology mark onto the substrate outside of the area of the composite image at the same time as projecting each of at least two of the image portions, and measuring the alignment of the metrology marks to determine the relative positions of the at least two image portions.