The first ordered fixed loop is revealed to be the Thief Knot

[Stagehand]

The first ordered fixed loop is revealed to be the Thief Knot.
     The first ordered non-trivial single-line knot form is the Trefoil Knot form, a form of three knot crossings.  The Trefoil is the model for a number of knots including the Overhand Stopper Knot, the Overhand Bend, and the Noose.  The Trefoil can be the pattern of a fixed loop when tying the Water Knot as a loop or when tying the Overhand Loop.  The Water Knot Loop is nearly two complete circuits of the Trefoil form with a total of six knot crossings.  The Overhand Loop is two nearly complete circuits of the Trefoil form with a total of six knot crossings. 
     The second ordered single-line knot form is the Figure Eight Knot form, a form with four knot crossings.  The Figure Eight Knot form is the pattern for a number of practical knots including the Retraced Figure Eight Loop with its two nearly complete circuits and eight total knot crossings. 
     A loop knot modeled on the pattern of the Thief Knot will follow the circuitry of the Figure Eight Knot form.  The circuit is completed with the working end making a fifth knot crossing.  Such a loop knot will have some stability when sufficiently tightened in a material with sufficient friction.  This fixed loop, the Thief Loop, is the first ordered for having just five knot crossings, a minimal number.   

[Dan_Lehman]

A loop knot modeled on the pattern of the Thief Knot
will follow the circuitry of the Figure Eight Knot form.
The circuit is completed with the working end making a fifth knot crossing.
Such a loop knot will have some stability when sufficiently tightened
in a material with sufficient friction.
This fixed loop, the Thief Loop, is the first ordered for having
just five knot crossings, a minimal number.

A too "minimal" number : it has six X-ings (2x3-each-half).

(There's an interesting redressing of the Thief that much
captures/has Fig.8 geometry, and ten X-ings!  And a securing
of the Grief looking impressive.  --things arising from my
musing about a recent article drawn to my attention, viz. :
 Tangled Physics: Knots Strain Intuitive Physical Reasoning,
by Sholei Croom and Chaz Firestone, inOpen Mind, Vol. 8; September 2024
)

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