Step 1: Read the idea in the question.
The theory talks about continents that were once joined and later drifted apart, which is the continental drift idea.
Step 2: Recall who is famous for this.
The scientist most strongly linked with continental drift is the German researcher Alfred Wegener.
Step 3: Remember the year and the supercontinent.
In 1912 Wegener proposed that all land was once a single mass called Pangaea, which then broke up.
Step 4: Rule out the others.
Ortelius and Pellegrini only noticed the matching coastlines much earlier, and Sorensen is not connected to this theory.
Step 5: Confirm the credit.
The full, organised theory belongs to Wegener.
Step 6: State the answer.
Hence the continental drift theory was put forth by Alfred Wegener.
\[ \boxed{\text{Alfred Wegener}} \]