2nd Saturday October (Installation)
4th Saturday January
4th Saturday March
2nd Saturday December
Four junior members of the Lodge of Progress 5017, having heard the then Provincial Grand Master, RW Bro The Rev Dr Joseph Moffett, observe on an Installation visit to Lodge of Progress, that with a membership of over one hundred, they should have another birth. There was already a Daughter Lodge, Prospect No. 6748, but contemplating that the then average time to the Chair was in excess of fifteen years, it was decided to form a new Lodge.
The name had to begin with PRO and after much research, a combination of Latin and Greek was selected: ‑ Probatus, meaning tried, tested and approved. The badge depicts the World chained and encircled by a ring representing the strength of Freemasonry Universal, also shown are the Dove of Peace, the Sword for Justice, and the Bible for Truth. The twelve Founders consisted of one Provincial Officer, one London Grand Rank and one other W. Brother and the rest were Master Masons; eight came from Herts and four from London Lodges, but eleven were Members of Royal Arch and the other a Provincial Officer in Mark. The Consecration was delayed to enable the Founding Secretary, Bro E L Jones to complete his three years as a Master Mason to qualify as a Founder. To this day, the Summons shows the Founders listed as they were at the Consecration and not by current or last Honours they held.