As a result of the Greek War of Independence, which had begun in 1821, and the Great Powers' intervention in the conflict after the Treaty of London in the Battle of Navarino (1827), the creation of some form of Greek state in southern Greece had become certain. In 1827, the Greek Third National Assembly entrusted the governance of the fledgling nation to Ioannis Kapodistrias, who arrived in Greece in January 1828. Alongside his efforts to lay the foundations for a modern state, Kapodistrias undertook negotiations with the Great Powers as to the extent and constitutional status of the new Greek state, especially during the Poros Conference of the Great Powers' ambassadors in September 1828.