An endoluminal prosthesis comprising: a prosthetic trunk comprising a tubular graft body, an open first end, an open second end, and a trunk lumen in fluid communication with the first end and the second end of the prosthetic trunk; a prosthetic branch comprising a tubular graft body, an open first end, an open second end, and a branch lumen in fluid communication with the first end and the second end of the prosthetic branch, the first end of the prosthetic branch joined to an intermediate portion of the prosthetic trunk, the branch lumen in fluid communication with the trunk lumen, the prosthetic branch extending from the prosthetic trunk and being movable with respect to the prosthetic trunk between a neutral configuration wherein the prosthetic branch is substantially aligned with the prosthetic trunk, a first biased configuration wherein the second end of the prosthetic branch extends away from the prosthetic trunk in a first direction to a first side of the prosthetic trunk, and a second biased configuration wherein the second end of the prosthetic branch extends away from the prosthetic trunk in a second direction to a second side of the prosthetic trunk opposite the first side; characterised by a first releasable steering member associated with the first biased configuration and a second releasable steering member associated with the second biased configuration, the steering members (70, 90) cooperatively retaining the prosthetic branch in the neutral configuration; wherein, upon release of one of the first steering member or the second steering member from the prosthetic branch, the prosthetic branch moves into one of the first biased configuration or the second biased configuration. a prosthetic trunk comprising a tubular graft body, an open first end, an open second end, and a trunk lumen in fluid communication with the first end and the second end of the prosthetic trunk; a prosthetic branch comprising a tubular graft body, an open first end, an open second end, and a branch lumen in fluid communication with the first end and the second end of the prosthetic branch, the first end of the prosthetic branch joined to an intermediate portion of the prosthetic trunk, the branch lumen in fluid communication with the trunk lumen, the prosthetic branch extending from the prosthetic trunk and being movable with respect to the prosthetic trunk between a neutral configuration wherein the prosthetic branch is substantially aligned with the prosthetic trunk, a first biased configuration wherein the second end of the prosthetic branch extends away from the prosthetic trunk in a first direction to a first side of the prosthetic trunk, and a second biased configuration wherein the second end of the prosthetic branch extends away from the prosthetic trunk in a second direction to a second side of the prosthetic trunk opposite the first side; characterised by a first releasable steering member associated with the first biased configuration and a second releasable steering member associated with the second biased configuration, the steering members (70, 90) cooperatively retaining the prosthetic branch in the neutral configuration; wherein, upon release of one of the first steering member or the second steering member from the prosthetic branch, the prosthetic branch moves into one of the first biased configuration or the second biased configuration.