Marian is a compound name combining Mary (Hebrew Miriam) and Anne (Hebrew Hannah) — like Mariana but with the English pronunciation. The name appears in the medieval English ballads of Robin Hood, where Maid Marian is Robin's beloved.
Marian was hugely popular in the early 20th century, peaking at #66 in 1928. Today Marian sits outside the top 1000 but is quietly returning.
Marian does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Marian reduce to 2, The Peacemaker. This is a traditional interpretive system, not a factual claim about the name.