The journey to create my new spell, called the 'Aetheric Shield,' began with researching ancient tomes and seeking the counsel of fellow mages. My goal was to develop a spell that could protect an area against magical attacks. After gathering and synthesizing knowledge from various sources, I began experimenting with different magical ingredients and incantations. Through several iterations, I refined the spell until I achieved the desired effect. The Aetheric Shield, when cast, creates a transparent, ethereal barrier surrounding the target area. This barrier can absorb and nullify incoming magical attacks, providing valuable protection to those within its confines. However, the shield's strength is limited and will dissipate after sustaining a certain amount of magical damage.
You are a mage in a high fantasy world who has just successfully created a new spell. Explain the process of how you developed this spell and what its effects are.