Around this time the northern part of the city became fashionable with the Anglo-Irish political and commercial establishment, who made up the ruling and commercial Ascendancy of the emergent semi-autonomous Kingdom of Ireland. Notable among these was the Gardiner family, Earls of Blessington and Viscounts Mountjoy, after which the second Phibsboro neighbourhood of Mountjoy developed. Gardiner Street, Gardiner Place, Gardiner Lane, Gardiner Row, Blessington Street, Blessington Court, Blessington Lane, Blessington Basin, Mountjoy Street, Mountjoy Square, Mountjoy Place and Mountjoy Parade – all in the vicinity – are named for the Mountjoy developer family connections. In 1789, Dublin Corporation commissioned the Royal Canal and a harbour built on Constitution Hill, connected to the main canal at Phibsboro by a spur. In many ways the history of Broadstone is the history of this canal. Though the branch line was completed by 1796, it was ten more years before the harbour was opened; construction continued for some years afterwards. The harbour's location was chosen for its proximity to the markets and the law courts. Bolton Street was the preferred site, but high land prices and objections from local residents forced its relocation. By 1807 a regular passage boat service was operating to Mullingar. In subsequent years the area was a hive of industry, with many hotels and inns and the trade boats using the wharfage and stores at the harbour. The canal was linked eventually with the River Shannon in 1817 after many financial difficulties and the majority of the main route still exists. In 1810 a reservoir, the Blessington Basin, was dug from the spur to supply water to the locality. Average annual tonnage on the canal in the 1830s was 80,000 tons and 40,000 passengers. The King's Inns is the oldest institution of legal education in Ireland, founded in 1542 during the reign of Henry VIII, and originally occupied property where the Four Courts now stand. When the Four Courts were built in the 1790s, King's Inns moved to Constitution Hill. The present building, designed by James Gandon, was built opposite the harbour and, like Gandon's Four Courts and The Custom House, was designed with its frontage on a waterfront. Construction began in 1800 and completed in 1823. Famous graduates since the move to Broadstone include Edward Carson, Patrick Pearse, Charles Haughey, Mary Robinson and Michael McDowell. Mary's Chapel of Ease, universally known as the Black Church, was built in 1830 and was designed by John Semple.