Her northern boundary still remained to be adjusted; but the embarrassments of both proprietaries with the crown, caused the controversy in this quarter to sleep nearly half a century. The mutual border outrages which meanwhile disturbed the debatable ground, led to the compact of the 10th of May, 1732, between Baltimore and the younger Penns, which provided, in the first place, for the extension of a line northerly, through the middle of the peninsula, so as to form a tangent to a circle drawn round Newcastle, with a radius of twelve miles. The northern boundary of Maryland was also to begin, not at the fortieth degree of latitude, but at a point fifteen miles south thereof; and in case the tangent before described should not extend to that point, it was to be prolonged by a line drawn due north from the point where the tangent met the circle; thus was ascertained the eastern extremity of the northern boundary line, which was thence to be extended due west. New obstacles intervened, however, to the execution of this agreement, which was subsequently carried into chancery, but on which no decision was had until 1750; and in the interval, some frightful excesses were committed by the borderers on both sides. The house of one Cresap, in Maryland, was fired by a body of armed men from Pennsylvania, who attempted to murder him, his family, and several of his neighbours, as they escaped from the flames. In retaliation, a little army of three hundred Marylanders invaded the county of Lancaster, and took summary measures to coerce submission to the government of Maryland. These mutual outrages occasioned, in 1739, an order from the king in council for the establishment of a provisional line; and in 1750, Chancellor Hardwicke pronounced a decree, which ordered the specific execution of the agreement of 1732. But Frederic, Lord Baltimore, the heir of Charles, with whom the agreement had been made, contending that he was protected from its operation by certain anterior conveyances in strict settlement, objected to the execution of the decree, until finally, and pending the chancery proceedings, a new agreement was entered into on the 4th of July, 1760, between himself and the Penns, which adopted that of 1732, and also the decree of 1750. Commissioners were appointed to run the lines accordingly, who in November, 1768, reported their proceedings to the proprietaries, and definitively adjusted the eastern and northern boundaries of Maryland, in the terms of the agreement before described. The northern line, from the names of the surveyors, is commonly known as "Mason and Dixon's line," so often referred to as the demarcation of the slave states from the others.