He mapped several islands. Tasman named the island of Tongatapu "t’ Eijlandt Amsterdam" (Amsterdam Island), because of its abundance of supplies. This name is no longer used except by historians. The most significant impact had the visits of Captain Cook in 1773, 1774, and 1777, followed by the first London missionaries in 1797, and the Wesleyan Methodist Walter Lawry in 1822. Around that time, most Tongans converted en masse to the Wesleyan (Methodist) or Catholic faiths. Other denominations followed, including Pentecostals, Mormons, Seventh-day Adventists, and most recently the Bahá'í faith. The islands were also visited by the Spanish under Francisco Antonio Mourelle in 1781 and Alessandro Malaspina (who unsuccessfully claimed Vavau for Spain) in 1793 and by the French under Marc-Joseph Marion du Fresne in 1772, Jean-François de Galaup, comte de Lapérouse in 1787, Fletcher Christian in 1789 and Antoine Bruni d'Entrecasteaux in 1793. In 1799, the 14th Tui Kanokupolu, Tukuaho was murdered, which sent Tonga into a civil war for fifty years. Finally, the islands were united into a Polynesian kingdom in 1845 by the ambitious young warrior, strategist, and orator Tāufaʻāhau. He held the chiefly title of Tu'i Kanokupolu, but was baptised with the name King George Tupou I. In 1875, with the help of missionary Shirley Baker, he declared Tonga a constitutional monarchy, at which time he emancipated the serfs, enshrined a code of law, land tenure, and freedom of the press, and limited the power of the chiefs. The islands were not fully surveyed until 1898, when the British warships and completed the task. Tonga became a British protected state under a Treaty of Friendship on May 18, 1900, when European settlers and rival Tongan chiefs tried to oust the second king. The Treaty of Friendship and protected state status ended in 1970 under arrangements established prior to her death by the third monarch, Queen Sālote. On 18 May 1900, to discourage German advances, the Kingdom of Tonga became a Protected State with the United Kingdom under a Treaty of Friendship signed by George Tupou II after European settlers and rival Tongan chiefs attempted to overthrow him.