The continuous-space symbiotic branching model describes the evolution of two interacting populations that can reproduce locally only in the simultaneous presence of each other. If started with complementary Heaviside initial conditions, the interface where both populations coexist remains compact. Together with a diffusive scaling property, this suggests the presence of an interesting scaling limit. Indeed, in the present paper, we show weak convergence of the diffusively rescaled populations as measure-valued processes in the Skorokhod, respectively the Meyer-Zheng, topology (for suitable parameter ranges). The limit can be characterized as the unique solution to a martingale problem and satisfies a "separation of types" property. This provides an important step toward an understanding of the scaling limit for the interface. As a corollary, we obtain an estimate on the moments of the width of an approximate interface. This is an electronic reprint of the original article published by the Institute of Mathematical Statistics in The Annals of Probability, 2016, Vol. 44, No. 2, 807-866. This reprint differs from the original in pagination and typographic detail. 1 4 J. BLATH, M. HAMMER AND M. ORTGIESE before Corollary 1.2. Recently, analogous results have been derived by Döring and Mytnik in the case ̺ ∈ (−1, 1) in [9, 10]. Returning to the continuous-space set-up, for ̺ = −1 (the stepping stone model) Tribe [27] proves a "functional limit theorem": For a pair of (continuous) functions (u, v), define R(u, v) := sup{x : u(x) > 0}, L(u, v) = inf{x : v(x) > 0}. (5)Note that for a solution (u t , v t ) t≥0 of the symbiotic branching model, the interface at time t is contained in the interval [L(u t , v t ), R(u t , v t )]. It is proved in [27] for ̺ = −1 and for continuous initial conditions u 0 = 1 − v 0 which satisfy −∞ < L(u 0 , v 0 ) ≤ R(u 0 , v 0 ) < ∞ that under Brownian rescaling, the motion of the position of the right endpoint of the interface t → 1 n R(u n 2 t , 1 − u n 2 t ), t ≥ 0, converges to a Brownian motion as n → ∞.The above results suggest the existence of an interesting diffusive scaling limit for the continuous-space symbiotic branching model (and its interface) for ̺ > −1. This is the starting point of our investigation. However, compared to the case ̺ = −1, the situation is more involved here: For example, the total mass of the solution is not necessarily bounded, and in particular, moments of the solution may diverge as t → ∞, depending on ̺. For instance, second moments diverge for ̺ ≥ 0. In order to state this result, which was obtained in [3]