The first 256 code points were made identical to the content of ISO-8859-1 so as to make it trivial to convert existing western text. Many essentially identical characters were encoded multiple times at different code points to preserve distinctions used by legacy encodings and therefore, allow conversion from those encodings to Unicode (and back) without losing any information. For example, the "fullwidth forms" section of code points encompasses a full Latin alphabet that is separate from the main Latin alphabet section because in Chinese, Japanese, and Korean (CJK) fonts, these Latin characters are rendered at the same width as CJK ideographs, rather than at half the width. For other examples, see Duplicate characters in Unicode.
প্রথম ২৫৬ কোড পয়েন্টকে কেন আইএসও-৮৮৫৯-১ এর সাথে অভিন্ন করা হয়েছিল?
to make it trivial to convert existing western text