Kiev or Kyiv?

Sometimes they write it Kiev, other times Kyiv? Why and what's the difference?

The answer to this question lies in history of Ukraine. Long time ago, during formation of Russia, Kiev became the capital of the future Slavic state, Russia. Bonds between Russian and Ukrainian people have being very strong for long-long time. In 18th century Ukraine achieved its independence from Poland. In 20th century, till 1991, Ukraine was a part of the Soviet Union (USSR), and the official language was Russian. Spelling of city names is based on their phonetic pronunciation. In Russian it sounds like "Kiev". That was the official English writing of the capital of Ukraine around the world for quite some time. Since 1991 Ukraine is an independent country. Again. Official language in Ukraine now is Ukrainian. In Ukrainian it sounds more like "Kyiv". Therefore, new writing of the city is "Kyiv", but the old writing "Kiev" formally is still in force, and even stays dominant in the world circulation, especially in official and information circles.

In the same way writing of the names of other Ukrainian cities is also split off, for example, Kharkov - Kharkiv, Lvov - Lviv, Chernovtsy - Chernivtsi, etc.