Preheat oven to 375 degrees. In a large bowl, combine artichoke hearts, spinach, mozzarella, parmesan, red bell pepper, mayonnaise, garlic, and black pepper. Mix well, and set aside.
Remove crescent roll dough from packages and separate into 16 triangles on a clean work surface. On a pizza stone or half sheet tray, arrange 8 triangles in a circle with the widest edges touching, about 3” from the edge of the pan (points will extend off the edge of the pizza stone or sheet tray). Matching up wide ends with those already in place, arrange remaining 8 triangles on pan pointing in the opposite direction (points will overlap in the center). Pinch dough triangles together at seams and press with fingertips to smooth.
Spoon filling evenly over seam of dough in a continuous circle. Beginning with the last triangle placed in the center of the pan, bring point of triangle straight across filling. Next, bring point of opposite outside triangle diagonally across point of previous triangle (the filling will show). Repeat, overlapping points of inside and outside triangles around filling to form a wreath. Tuck last end under first.
Brush top of wreath with egg wash and bake until bubbly and golden brown, 25-30 minutes. Brush surface of wreath with pesto and allow to rest at least 10 minutes before serving, with marinara sauce for dipping.