In Southeast Asia, the concept of adat and its meanings were first formulated in the Islamised Malay-speaking world, apparently to distinguish non-Islamic from Islamic practices. In the 15th century, the Melaka empire developed a code of international shipping law, "Undang-Undang Laut Melaka", and a civil and commercial code, "Undang-Undang Melaka", which was heavily Islamic but with extensive adat influences. These codes would later spread across the region and became the legal source for local jurisprudence in major regional sultanates like Brunei, Johor, Pattani and Aceh.