He is believed to have been a second lieutenant in an artillery company.

It was made up of eight artillery companies from eastern Pennsylvania.

The artillery company had set up its cannons about four miles to the west.

At the start of the war, he organized an artillery company and was chosen as its captain.

One of these companies was a special artillery company.

A royal artillery company soon spread its tents on the Common.

After living there for some time he was permitted to return to Boston, and in 1651 became captain of the artillery company.

Presumably Robertson returned to his artillery company because there is no further record of him.

The battalion grew to eight companies, plus the attached artillery company.

Two of the artillery companies existed since early 1776.