A magic circle is a circle of space marked out by practitioners of some branches of ritual magic, which they generally believe will contain energy and form a sacred space, or will provide them a form of magical protection, or both. It may be marked physically, drawn in a material like salt, flour, or chalk, or merely visualised. Techniques Traditionally, circles are believed by ritual magicians to form a protective barrier between themselves and what they summon. One text known as the Heptameron says of the circle, 'But because the greatest power is attributed to the circles; (for they are certain fortresses to defend the operators safe from the evil spirits); in the first place we will treat concerning the composition of a circle.' Moreover, as magician and historian Jake Stratton-Kent writes, 'In short a circle is not an obsolete symbol of a superstitious fear of spirits, but an intentionally created ritual space for various purposes. It is not always required for all kinds of ritual work, but neither is it of no value, quite the contrary. Making sacred space is among the most primal of rituals, such intentional actions are as worthy of the term psychoactive as any substance.' Circles may or may not be physically marked out on the ground, and a variety of elaborate patterns for circle markings can be found in grimoires and magical manuals, often involving angelic and divine names. Such markings, or a simple unadorned circle, may be drawn in chalk or salt, or indicated by other means such as with a cord. Some traditions include tracing or circumambulation. Uses In Sumer The Sumerians called the practice of using ritual circles zisurrû. In Judaism Examples of Jewish customs showing the use of the magic circle can be found in the birth protection rituals of Alsace and the surrounding area. As early as 1560, a text by the rabbi Naphtali Hirsch ben Elieser Treves notes a custom in which a circle is drawn around the birthing woman to protect her from Lilith and demons. This was done using a Krasmesser (circle knife) which would be wielded by the midwife or the father of the child. Paul Christian Kirchner’s description of Jewish birthing customs from 1734 includes an illustration showing a knife or a sword near the bed, and likewise Johann Christian Georg Bodenschatz describes a sword placed near the pregnant woman in the eighteenth century,