The Treaty of Waitangi is a treaty which was signed in 1860 and was designed to provide Maori citizens with the rights of British citizens and ownership of their own lands on the North Island of New Zealand. The Treaty of Waitangi was not a wholly successful treaty, however, as the Treaty of Waitangi ultimately was instituted in multiple different languages, specifically English and Maori, and the differences in the Treaty of Waitangi which arose simply as a result of the language used to write the treaty led to significant differences in interpretation of the exact contents of the treaty.
For example, the British signers of the Treaty of Waitangi believed that the treaty was giving them full sovereignty over New Zealand, even as it was giving the Maori people the rights of citizens and the right to the property on which they lived. The Maori people had a number of different understandings, however, which led o conflict with the British understanding.
The Treaty of Waitangi is thus ultimately seen as a founding document for New Zealand in the form in which it exists today, but this is not without a great deal of controversy, as the Maori people of New Zealand believe that there have been many breaches of the Treaty of Waitangi, most of which have been met with no redress.
This is exacerbated significantly by those different versions of the Treaty of Waitangi and by the fact that when the Maori raised grievances, they were often unable to actually get the attention of the necessary parties in the British government of New Zealand.