The British occupied Salsette in 1774, and it was formally ceded to the East India Company in the 1782 Treaty of Salbai. In 1782, William Hornby, then Governor of Bombay Presidency, initiated the project of connecting the isles of Bombay. By 1845 the seven southern islands had been connected to form South Mumbai, with an area of 435 km². Railway viaducts and causeways were built in the 19th century to connect Bombay Island to the mainland via Salsette. The channels separating Mumbai from Salsette and Trombay were bridged by the Sion Causeway in 1803. Accessibility considerably increased after construction of this causeway. Mahim and Bandra were connected by the Mahim Causeway in 1845. These railway lines and roads encouraged wealthier merchants to build villas on Salsette Island. By 1901, the population of Salsette had increased to 146,993 and the region began to be referred to as Greater Mumbai.