1. The cult of Mithras was Christianity's main rival at the time of Constantine.

2. As France's main rival, Britain had resisted revolutionary ideas and retained its traditional units.

3. The company is in a position closely Analogous to that of its main rival

4. Castile is Aragon's main rival, and Spanish ambitions have them working to absorb Aragon into a common Spanish state

5. Betamax, also known as simply Beta, is a defunct analog home video format introduced on 10 May 1975 by Sony, one year before its main rival, the similar videotape format VHS from JVC