The Rev. James Magrath, son of Thomas Magrath, was born in county Roscommon, Ireland. He graduated from Trinity College, Dublin, in 1790, and entered holyorders. After graduating he married Mary and settled in the parish of Shankill where he planned to remain for the rest of his life. He also held commissions of the peace for seven counties, and was deputy governor in county Roscommon.

He came from a family whose sons had been Irish Protestant ministers for centuries. In the Reformation a former Franciscan monk, Mile Magrath, left the Catholic church and was appointed Archbishop of Cashel by Queen Elizabeth I.

By the early 19th century there was an outbreak of troubles in Ireland which made it impossible for Magrath to remain in Ireland.

In 1827, at the age of 58 years, Rev. James Magrath set out with his family for Canada where he felt there would be a promising future for his sons. Rev. James Magrath was soon offered the church recently built beside the Credit River. He bought land that was relatively cheap and built his home and rectory called Erindale.

During his first winter at the St. Peter’s Church, also known as the Toronto Mission, he would brave the storms to be at his church, only to discover that he was the only one who made the effort. Religion, he reported "was in a deplorable state". Drinking, swearing and Sabbath-breaking were all "common offences". He did not get any sympathy from his Bishop, but was told to expand his parish to include the local native Indian settlements. To this request, Magrath only grumbled that his parish was already too large since it was "bounded by the Rocky Mountains to the west and by the North Pole". There was an element of truth in this statement, since there was no Anglican church to the north of the Toronto Mission at that time.

Magrath was a popular minister in this pioneer community. It was noted that "his old world courtesy appealed to the upper classes and his kindness appealed to the lower classes". It was said that no one whether parishioner or not, went away hungry from his door. Magrath lived to a great age and would not allow a curate to help him until his eighties. He died at Erindale at the age of 82 years.

Rev. James Magrath shaped and influenced the local pioneer area more than anyone else,and it is fitting that the area was named Erindale after his home and estate.