Could a later marriage settle Russian royal legitimacy?

Would a later marriage in Russia make the children legitimate?

It depends on the period and the influence of the Russian Orthodox Church, with royal succession creating a particular need for an unchallenged claim.

A later marriage's effect depends on the period and the strength of the Russian Orthodox Church. Royal succession made questions of birth and marriage especially sensitive. A monarch needed a claim that appeared beyond challenge, so the effect of a later marriage has to be considered in that setting.