[ebb tide]

This was well after Martin Luther’s time who I’m sure would have disagreed with both views.

Did you not read the article?

It is a sweet and pious belief that the infusion of Mary's soul was effected without original sin; so that in the very infusion of her soul she was also purified from original sin and adorned with God's gifts, receiving a pure soul infused by God; thus from the first moment she began to live she was free from all sin" (Sermon: "On the Day of the Conception of the Mother of God," 1527)

[HarleyD]

If he held such a view then I would say that Luther was wrong. I'd like to hear Catholics admit that their Pope is wrong.

However, I'd suggest a little further research on Luther's views:

2. On the Day of the Conception of the Mother of God, 1527

The next tidbit offered by Marshall is the following Luther quote:

"It is a sweet and pious belief that the infusion of Mary’s soul was effected without original sin; so that in the very infusion of her soul she was also purified from original sin and adorned with God’s gifts, receiving a pure soul infused by God; thus from the first moment she began to live she was free from all sin" - Martin Luther's Sermon "On the Day of the Conception of the Mother of God," 1527.

The sermon this quote was taken from is not included in the English edition of Luther’s Works, and to my knowledge, the complete sermon has not been translated into English. This quote made its way into a cyber space when a Romanist about 10 years ago began posting it after he took it from Roman Catholic historian Hartmann Grisar's book, Luther Vol. IV (St Louis: B. Herder, 1913). Grisar uses this quote, but what my Romanist friends typically leave out is his analysis:

The sermon was taken down in notes and published with Luther’s approval. The same statements concerning the Immaculate Conception still remain in a printed edition published in 1529, but in later editions which appeared during Luther’s lifetime they disappear.

The reason for their disappearance is that as Luther’s Christocentric theology developed, aspects of Luther’s Mariology were abandoned. Grisar also recognizes the development in Luther's theology. In regards to the Luther quote in question, Grisar says (from a Roman Catholic perspective):

As Luther’s intellectual and ethical development progressed we cannot naturally expect the sublime picture of the pure Mother of God, the type of virginity, of the spirit of sacrifice and of sanctity to furnish any great attraction for him, and as a matter of fact such statements as the above are no longer met with in his later works.

Did Martin Luther believe in the Immaculate Conception of Mary?

Luther's views on Mary developed not unlike Augustine's views on grace, election and predestination. Many today Catholics disagree with Augustine on these matters but they were embodied in the Council of Orange.