In 1763, he began employment as the attorney for Sir William Johnson in Albany. Johnson had commanded the Iroquois and New York colonial militia forces during the French and Indian War, the North American theatre of the Seven Years' War in Europe. His role in the British victory at the Battle of Lake George in 1755 earned him a baronetcy and his capture of Fort Niagara from the French in 1759 brought him additional renown. Johnson served as the British Superintendent of Indian Affairs for the northern district from 1756 until his death in 1774, working to keep American Indians allied with the British. In letters to Johnson, Silvester wrote that he met with Witham Marsh concerning wrongs committed by Indians. Silvester was subsequently appointed "clerk of the peace." In 1767, he moved to the Van Schaack estate in Kinderhook, and began his practice of law as the first attorney in Kinderhook. Among the students who began the study of law in his office were: Peter van Schaack ; Francis Silvester, his son; and Martin Van Buren, who later became the 8th President of the United States. Van Buren began his legal training with Silvester and his son Francis in 1796, before Van Buren had reached the age of 14. When Van Buren first began his legal studies, he often presented an unkempt appearance in rough, homespun clothing. It was the Silvesters who suggested that Van Buren could improve his professional prospects by dressing fashionably and taking care in how he appeared in public; he heeded the advice and patterned his clothing, appearance, bearing and conduct after theirs. After six years under the Silvesters, the elder Silvester and Democratic-Republican political figure John Peter Van Ness suggested that Van Buren's political leanings made it a good idea for him to complete his education with a Democratic-Republican attorney. Van Buren accepted their advice and spent a final year of apprenticeship in the New York City office of John Van Ness's brother William P. Van Ness, a political lieutenant of Aaron Burr.
During the American Revolutionary War, Silvester backed the patriot cause and held a variety of positions in New York including: member of the Albany Common Council in 1772, member of the Committee of Safety in 1774, and a member of the First and Second Provincial Congresses in 1775 and 1776. His wife's family, the Van Schaacks, were Loyalists, and some historians have suggested that Silvester's in-laws may have influenced him to take a reduced role as the Revolution progressed.
On August 16, 1764, he married Jannetje "Jane" Van Schaack, daughter of Cornelius Van Schaack and Lydia Van Dyck. Cornelius Van Schaack owned a large estate in Kinderhook, New York. Jane was the elder sister of Peter van Schaack, who married the daughter of Henry Cruger, a wealthy New York merchant. Together they had:
Francis Silvester, who married Lydia Van Vleck Van Schaack, a niece of Peter van Schaack and foster daughter of David Van Schaack
*Peter Henry Silvester, who married Catherine Susan Bronk
Silvester was a warden of St. Peters Church in Albany in 1773, and was listed as a vestryman in the Church's charter of incorporation, granted by King George III on April 25, 1769. Silvester resided in Kinderhook, where he died on October 15, 1808, aged 74 years. He was interred in the "Old Van Schaack Cemetery", over which the Kinderhook Reformed Dutch Church and Cemetery were built in 1814. The exact location of his grave is not known.
Memorials
The SS Peter Silvester, an American merchant marine ship built for the United States Maritime Commission in service from 1942 to 1945 was named for Peter Silvester.
