(22) In order to ensure legal certainty and safeguar
d trade mark rights legitimately acquired, it is appropriate and necessary to lay down, without affecting the principle that the later
trade mark cannot be enforced against the earlier
trade mark, that proprietors of European
trade marks should not be entitled to oppose the use of a later
trade mark when the later
trade mark was
acquired at a time when the earlier
trade mark could not be enforced against the later
trade ...[+++] mark.