"John Mason, soldier, was born in the north of England in 1601. The first record of him is as a lieutenant under Sir Thomas Fairfax, serving in the Low Countries from April to July, 1630. He appeared in Dorchester before December, 1632, to serve as magistrate of Massachusetts Bay Colony in searching for a pirate named Bull. In 1634, he was one of a committee to plan the fortifications of Boston Harbor and erect a battery on Castle Island.
In March, 1635, he was elected to represent Dorchester in the General Court, and was given permission by that body to accompany a small band of the pioneers who opened the way for settlers desiring to found new homes on the banks of the Connecticut River. These pioneers were followed in June by a consider able body under Hooker and Stone, and they made settlements at Windsor, where Captain Mason was magistrate, and also at Hartford and Wethersfield, and in 1636 they numbered 800, 250 of whom were capable of bearing arms.
When 30 of the settlers had fallen victims to the 400 Indians who surrounded them, the General Court of Connecticut asked aid of the Plymouth and Massachusetts Bay Colonies, and they agreed to furnish 40 and 160 men respectively to help suppress the Indians. Connecticut raised 90 men, under command of Captain Mason, and on May 1, 1636, war was declared against the Pequot tribe.
On May 10, Mason started down the river, arriving at Saybrook, May 17, where Captain Underhill joined him with 20 men. This enabled Mason to send 20 of his own men to protect the women and children at Windsor, and the expedition proceeded on May 19 to the Narragansett country outside the Connecticut boundary, although this was contrary to the instructions of the General Court.
Arriving on Saturday evening. May 20, they remained in their boats over the Sabbath [Sunday], and were detained by a storm till Tuesday, when they landed at the foot of the hill overlooking Point Judith, where Mason called upon Canonicus, chief of the Narragansetts, for safe passage through his country in order to punish their common enemy, the Pequots. Here he received notice from Roger Williams of the arrival of Captain Patrick with 40 men from Massachusetts Bay.
Mason, however, impatient to take the Pequots by surprise, decided not to wait for Patrick’s arrival, and he sent his boats to the mouth of the Pequot River and with 77 white men, 60 Mohegan and 200 Narragansett Indians, he took up the march, and the next day was joined by Uncas with 200 Niantic Indians.
Mason surprised the Pequot fort, May 26, gained entrance to the camp with 16 men, while Captain Underhill, also with 16 men, effected an entrance on the other side. The remaining colonists with the friendly Indian allies formed a line that reached entirely around the fort and prevented the escape of the enemy. Captain Mason ordered his men to apply the torch and in a few minutes the entire camp was on fire. In the confusion the 32 attacking colonists took their place with the other guards, and the Indians were slain as they emerged from the fort. Only 7 Pequot warriors escaped and 7 were made prisoners. The 300 Pequots occupying the other fort under Sassacus fled panic stricken and were mercilessly driven before the retiring colonists as far as Saybrook, the remnant escaping into New York.
This decisive action put an end to Indian wars in New England for forty years. The General Court of Connecticut, on Mason’s return to Hartford, made him chief military commander of the colony, with the rank of major, which was equivalent to major-general. His action in slaying the Pequots was approved by Roger Williams, who designated him a "blessed instrument of peace for all New England."
He removed to Saybrook when that fort passed to the control of the colony, and he was made captain of the fort and commander of the forces of the United Colonies. In 1659, he settled in Norwich, which place he helped to found. He was a magistrate, 1643-68, and deputy governor, 1660-70. The Commonwealth erected a monument to his memory on Pequot Hill, Groton, Connecticut, surmounted by a heroic-size statue in bronze. It was unveiled June 26, 1889. He wrote an account of the Pequot War, which was published by Increase Mather in his Relation of Troubles by the Indians (1677). He died in Norwich, Connecticut, January 30, 1672.
— Lamb's Biographical Dictionary of the United States, 1900 (edited)