The concept of **Da'at** (Knowledge) as a quasi-Sefirah in Kabbalah existed conceptually when the Sefirot were first systematized in the 12th–13th centuries, but its role in the Tree of Life diagram—particularly its placement as a "hidden" or non-standard node—was not fully integrated when the tree formation emerged in the 14th century. Below, I’ll trace the development of Da'at in relation to the Tree of Life’s formation, addressing your question directly and concisely.

### Da'at in Early Kabbalah - **Origins in Early Texts (12th–13th Century)**: The term Da'at appears in the *Sefer Yetzirah* (2nd–6th century CE), an early Jewish mystical text, where it is associated with consciousness or mystical awareness but not yet as a Sefirah. In the *Sefer ha-Bahir* (c. 1170s, Provence), Da'at is occasionally referenced as a mediating principle or state of unity between Chokmah (Wisdom) and Binah (Understanding), but it’s not explicitly listed among the ten Sefirot. The *Zohar* (c. 1280–1290, Spain, attributed to Moses de León) further develops Da'at as a kind of spiritual knowledge or divine awareness, often symbolizing the harmonious interaction of Chokmah and Binah (the intellectual Sefirot). However, the *Zohar* primarily focuses on the standard ten Sefirot (Keter, Chokmah, Binah, Chesed, Gevurah, Tiferet, Netzach, Hod, Yesod, Malkhut) and treats Da'at as a derivative or implicit quality, not a formal Sefirah. - **Role in the Tree’s Formation (14th Century)**: When the Tree of Life diagram solidified in the 14th century (as discussed in my previous response, with early forms in Spanish Kabbalistic manuscripts and Joseph Gikatilla’s *Sha'arei Orah*, c. 1290), the standard structure included only the ten Sefirot. Da'at was not consistently depicted as a node in these early diagrams. Instead, it was understood theologically as an emergent state—sometimes called the "external aspect" of Keter or a synthesis of Chokmah and Binah—representing the human or divine capacity to know God through unity of intellect and emotion. Early tree diagrams, like those from the 1280s–1300s, focused on the ten Sefirot arranged in three pillars, with no explicit place for Da'at. For example, the "Tree of Wisdom" (*Ilan Chochmah*) and similar schematics from this period lack a Da'at node, prioritizing the standard ten. ### Integration of Da'at into the Tree - **Later Development (15th–16th Century)**: The explicit placement of Da'at as a quasi-Sefirah in the Tree of Life gained prominence in later Kabbalistic traditions, particularly after the 15th century. Some Kabbalists, especially in the Safed school of the 16th century (e.g., Moses Cordovero and Isaac Luria), began to describe Da'at as a "hidden" or "eleventh" Sefirah, located between Keter and Tiferet or as a midpoint between Chokmah and Binah. This reflects its role as a bridge between the intellectual (upper) and emotive (lower) Sefirot. However, Da'at was not counted among the ten Sefirot because it was seen as a state of consciousness rather than a structural emanation of divine essence. In Lurianic Kabbalah (post-1570s), Da'at became more prominent, especially in discussions of the *tzimtzum* (divine contraction) and the breaking of the vessels, where it symbolizes restored unity after cosmic rupture. Some Lurianic diagrams included Da'at as a dotted or implied node, but this was not universal. - **Visual Representation**: The earliest Tree of Life diagrams to include Da'at explicitly appear in post-medieval Kabbalistic works, particularly in the 16th–17th centuries. For instance, Christian Kabbalists like Johann Reuchlin (whose 1516 *Porta Lucis* popularized the tree diagram) and later Athanasius Kircher (17th century) sometimes referenced Da'at in their interpretations, influenced by Jewish sources. However, the standard Jewish tree diagrams of the 14th–15th centuries, such as those in Hebrew manuscripts or early printed books (e.g., Mantua, 1494), typically omitted Da'at as a distinct node. Its inclusion became more common in esoteric traditions, including Hermetic Qabalah (19th–20th centuries), where Da'at is often depicted as a "non-Sefirah" or abyss, especially in systems like the Golden Dawn. ### Conclusion When the Kabbalistic Tree of Life was first formed in the 14th century, the concept of Da'at existed in Kabbalistic thought as a theological principle (knowledge or unity of divine attributes), but it was not a standard part of the ten-Sefirot diagram. It was only later, particularly in the 16th century with Lurianic Kabbalah and Christian adaptations, that Da'at began to be visualized as a quasi-Sefirah in some Tree of Life configurations, often as a hidden or mediating node. Thus, while Da'at was known conceptually in the 12th–13th centuries, its placement in the tree’s structure was a later development, not integral to the initial formation of the diagram. For further reading, Gershom Scholem’s *Kabbalah* or Daniel Matt’s *Zohar* translations offer detailed insights into these concepts.