Penn sent three commissioners to supervise the settlement and to set aside 10,000 acres (40 km2) for the city. The commissioners bought land from Swedes at the settlement of Wicaco, and from there began to lay out the city toward the north. The area went about a mile along the Delaware River between modern South and Vine Streets. Penn's ship anchored off the coast of New Castle, Delaware, on October 27, 1682, and he arrived in Philadelphia a few days after that. He expanded the city west to the bank of the Schuylkill River, for a total of 1,200 acres (4.8 km2). Streets were laid out in a gridiron system. Except for the two widest streets, High (now Market) and Broad, the streets were named after prominent landowners who owned adjacent lots. The streets were renamed in 1684; the ones running east–west were named after local trees (Vine, Sassafras, Mulberry, Cherry, Chestnut, Walnut, Locust, Spruce, Pine, Lombard, and Cedar) and the north–south streets were numbered. Within the area, four squares (now named Rittenhouse, Logan, Washington and Franklin) were set aside as parks open for everyone. Penn designed a central square at the intersection of Broad and what is now Market Street to be surrounded by public buildings.