Why is the lodge tyled and what does the Tyler guard against?

Tyling a lodge derives from the operative art of building, where a tiler completed a structure by placing the roof of tiles, rendering those within secure from intrusion 12. In speculative lodges, the Tyler performs a parallel function when the lodge is organized by closing the outer door and covering the precincts from outside interference 2.

The Tyler guards the assembly against two primary classes of intruders: eavesdroppers and cowans 1. Historically, an eavesdropper was a thief who attempted to listen beneath the eaves of a building to acquire by stealth what he would not earn through labor 1. A cowan was an uninstructed or half-trained mason who laid field stones without mortar or proper squaring, or an apprentice attempting to masquerade as a Master Mason 1. Operative assemblies guarded their meetings against both the thief and the ill-qualified worker to preserve their trade and security, a practice maintained in symbolic lodges 1.

To maintain this protection, the Tyler remains outside the door, traditionally armed with a drawn sword 2. This blade was historically wavy in shape, made in allusion to the flaming sword placed at the east of the Garden of Eden to keep the way of the tree of life 2. To outsiders, the weapon serves as a warning and a challenge, while to the brethren assembled inside, it acts as a guard and protection 2. Legitimate communication between the lodge and the outside occurs only through the door upon a regular alarm duly reported and ordered by the Master 2.

The sword carried by the Tyler serves to outsiders as a challenge and a warning, while to lodge members it signifies a guard and a protection 2. Historically, the weapon was wavy in shape, referencing the flaming sword placed at the east of the Garden of Eden that turned every way to keep the way of the tree of life 2. It was traditionally kept drawn and without a scabbard, denoting that the officer must ever be ready for the defense of his post 2.

In Masonic symbolism, the sword is understood as an emblem of power and authority, rather than one of blood, battle, or death 3. It prompts Masons to carry a Tiler's sword in their own hearts by observing silence and circumspection, maintaining the security of the lodge through brotherly love rather than physical force 3. The United Grand Lodge of England designates a sword as the official emblem for the office of Grand Tyler.

The exact date when a door guardian first went on duty in a Masonic lodge is not positively known 1. The office originated in the practical necessity of operative Masons, who were required to protect their working assemblies from unauthorized entry 1. These intruders included eavesdroppers who attempted to learn by stealth what they would not learn by work, as well as uninstructed builders who lacked proper qualifications 1.

The title of Tyler arose by analogy to the operative building trade 1. In actual construction, the tiler was the workman who placed the roof or tiles upon a structure, which completed the building and rendered those inside secure from external intrusion 1. The officer assigned to guard the door against outside interference was consequently given the name of Tyler to reflect that same protective function 1.

While guarding the lodge door stems from these operative origins 1, formal organizational structures were instituted during the early grand lodge era, such as an office established in 1738 to be filled annually by appointment 2. Through these developments, the central purpose of the Tyler has remained constant: securing the precincts of the lodge so that the brethren within may conduct their labors without intrusion 1.