The topics discussed in this paper are the definition of onomastics, the problem of understanding what proper names are and how they can be distinguished. Two basic types, anthroponyms (names of people) and toponyms (place-names) are in the further text discussed in more detail. Prior to that, some relevant sources naming both personal and place names are stated. These sources are divided according to three periods: Old English, Middle English and Modern English period. The most important one is Doomsday Book which is the prime- source for Old English and early Middle English people and place names. After that, personal names and their development (or how they came into English language) are stated. They are also split in three periods. Cecily Clark and Richard Coates are the authors who wrote the most about English place-names and names of people and how they developed. Clark uses terms ‘personal name’, ‘idionym’, ‘by-name’ and ‘nickname’ when she addresses different kinds of people-names. The same terms are used in this paper. The first languages which had influence on what was to become English language were Latin and Celtic language. After them, North- Germanic tribes came and with them they brought their names. In the Middle English period, single idionyms were supplanted with combinations of family and baptismal names. Also, by-names became universalized. When place-names are concerned, they are also divided into the same three periods and they had been under the same influence as names of people.