As the name "computer" suggest that a computer is a machine that can compute or calculate. Use of such computing devices started with the development of ABACUS about 3000 BC.
Different computing devices came into existence till 1960 till first digital calculator appeared. Then there was a series of inventions in field of computing machines.
Some of those machines are -
1. Pascaline built by Blaise Pascal(1642)
2. Lebnitz calculator developed by Von Lebnitz(1671)

But the origin of modern computers (which are characterized by the property that they can be programmed) can be traces in 1834 with the development of the computing machine called "Analytical Engine".
It was developed by Charles Babbage (English mathematician). This machine was considered as the first "programmable digital mechanical computer".
Lady Ada Lovelace  wrote many operating instructions for this machine developed by Babbage, therefore she is considered to be the " FIRST COMPUTER PROGRAMMER".
And Charles Babbage therefore known as the "FATHER OF COMPUTER".