Conditions on the frontier, however, made it necessary in 1662 to unite Westmoreland and Northumberland counties for administrative purposes "until otherwise ordered by the governor."[13] There is no record of the date of his later decision to separate the two counties but he must have done so. [13] Hening, Vol. ii, p. 151. Similarly, there is no definite record of the establishment of Stafford County. The first legislative reference to Stafford is in an Act[14] exempting the inhabitants of Stafford because of the "newnesse of its ground" from a general requirement laid upon counties to employ a weaver and set up a public loom. In this year of 1666 Stafford sent a delegate to the General Assembly. The County, however, must have been in existence earlier since there is a record of the Stafford County Court Book which on page one relates to a meeting of the Court for the County on May 27, 1664.[15] The boundaries of the County are nowhere set forth at this early date, but that they encompassed the Arlington area is clear from a direction of the Legislature in 1676 that a fort be established "on Potomack river at or near John Mathews in the county of Stafford."[16] John Mathews' land was on the lower side of Great Hunting Creek[17] but there would have been no reason at that time to erect a separate county to the north. [14] Act VIII, October 1666. [15] Robinson, _Virginia Counties_, p. 87. This court book may also be inspected at the Stafford County Court House. [16] Hening, Vol. ii, p. 327. [17] Stetson, _Four Mile Run Land Grants_, p. 1. There were no further changes affecting the county within which Arlington lay until 1730 when Prince William County was formed. An Act of the General Assembly declared that after March 25, 1731, "all the land, on the heads of the said counties [Stafford and King George] above the Chopawansick Creek, on Patomack river, and Deep run, on Rappahannock river and a southward line to be made from the head of the north branch of the said creek to the head of the said Deep run, be divided and exempt from said counties ... and be made a distinct county, and shall be called and known by the name of Prince William County."[18] [18] Acts of Assembly, May 1730, Chapter XVII. Hening, Vol. iv, p. 303. It was not many years until Fairfax County came into being: