Seal assemblies and methods for forming them are described. Aspects of the seal assemblies include a seal ring made of a relative soft material supported by a specially configured backing ring made of a much higher modulus material, such as ferrous and non-ferrous metal or engineered plastic. The seal assemblies may optionally include a retaining ring to prevent slippage relative to the environment or housing in which they are placed and to prevent shuttling. The seal assemblies may also optionally include an energizer to alter the force generating by a sealing lip on the seal ring. The seal assemblies preferably include a rigid hoop ring to minimize shrinkage due to thermal cycling.