Contact between Irish and English began in the late twelfth century with the coming of the Anglo-Normans, along with some English who settled in the towns of the east coast. The relationship of Irish to English varied over the centuries, with Irish being a superstrate to English in the first few centuries. However, during the Elizabethan period and afterwards, English emerged clearly as the superstrate vis a vis Irish and has remained so ever since. The linguistic effects of the contact between Irish and English is seen most clearly in the historical language shift which took place in Ireland with speakers of Irish in the past few centuries. The aim of this chapter is twofold: first to provide the necessary historical and demographical background to understand the shift and then to use this information as a basis for a more general review of contact scenarios.