The original 1807 Act only allowed for British ships to be searched and applied only to British subjects. The slave trade on the African coast therefore continued, though without, at least on a legal basis the presence of British slavers. However, in 1810, under considerable diplomatic pressure, a convention with Portugal was signed widening the mandate of the Royal Navy. In 1815, Portugal strengthened their anti-slavery legislation by abolishing all trade north of the equator, allowing the Royal Navy a much freer hand. With the conclusion of the Napoleonic Wars, Britain obtained treaties with several other powers including France, which abolished its trade entirely in 1815 (but did not commit to right of search), and Spain, which agreed to cease trade north of the equator in 1818, and south of the equator by 1820. A clause was also inserted into the Congress of Vienna which called for the eventual abolition of the trade by all signatories. In 1826, Brazil signed an agreement similar to that of Portugal, and ceased trade north of the equator.