Castel Sant'Angelo Solutions

The fictional Castel Sant'Angelo
There are multiple spellings for many of these (e.g. you can answer question 4 with either "and" or "&")

1. Roman Holiday
2. Spectre
3. River Tiber
4. Angels and Demons
5. Passetto di Borgo
6. Assassin's Creed: Brotherhood (accepted with or without the colon)
7. Assassin's Creed 2
8. Tosca
9. Giacomo Puccini
10. Either Endymion or The Rise of Endymion
    This gives you the Castel Word ANGLO.

The Tomb of Hadrian
The three podcasts in clue 8 (8A, 8B, 8C) and the three in clue 11 (11A, 11B, 11C) must overlap by at least one podcast. It cannot be 8A, 8B, 8C-11A, 11B, 11C (Father Benedict and Sister Dido are separate podcasts), or 11A, 11B-8A, 11C-8B, 8C (Pope goes the Weasel and Yes we Vatican are separate). It cannot be 11A-8A, 11B-8B, 11C-8C, as Father Benedict did not discuss collecting clowns (clue 3) or 8A, 8B-11A, 8C-11B, 11C as Sister Dido did not discuss homebrewing (clue 5). Father Benedict was first, homebrewing 2nd, Pope Goes the Weasel and clown figurines 3rd, Yes We Vatican 4th, and Sister Dido fifth. Bird of Prey is not 1st or 5th (clue 6), so its 2nd. Fire the Canons is not 1st (clue 9), it must be 5th and drag racing 4th. The Missionary Position must be 1st by elimination. The Missionary Position did not discuss erotic crosswords (clue 7) so erotic crosswords were 5th, and strip poker parties 1st. Monsignor Carmine's must be 2nd (clue 4). Sister Abigail is not 3rd (clue 2), so she was 4th and Father Enrico was 3rd. If Monsignor Carmine’s podcast has been put out X+6 months, then Sister Abigail’s has been put out 2X+6 (clue 2). Per clue 1, Father Enrico’s put out 4 more than 1/4 of (2x+6)-4, or .5X + 4.5. Per clue 3, Father Benedict was published .5X+9.5 podcasts, and per clue 7, Sister Dido has published .5X+15.5 podcasts. No one has published more than 24 podcasts, so X is Taking 1, 3, 5, 7 or 9. No one has published 8 or 11 podcasts (clue 10), eliminating X=1, 3, 5, and 7. X must be 9, and the number of podcasts in order are 14, 15, 9, 24, and 20. In summary:
• 1. Father Benedict Bonnaro, The Missionary Position (14 mos.) discussed strip poker parties
• 2. Monsignor Carmine Caravaggio, Bird of Prey (15 mos.) discussed homebrewing in the Sistine Chapel
• 3. Father Enrico Ennigelli, Pope Goes the Weasel (9 mos.) discussed collecting clown figurines
• 4. Sister Abigail Adams, Yes we Vatican (24 mos.) discussed drag racing (racing in drag)
• 5. Sister Dido Danielle, Fire the Canons (20 mos.) discussed erotic crosswords
Solving this gives you the Castel Word PERTURB.

The Papal Apartments
You need the most common names of popes 1. Boniface 2. Benedict 3.Sergius 4. Adrian 5. Innocent 6. Gregory 7. Paul 8. Anastasius 9. Sixtus 10. Urban 11. Clement 12. Eugene 13. Pius 14. John 15. Celestine 16. Leo 17. Stephen
Taking the letters in the coloured boxes in rainbow (ROYGBIV) order, you get BECAME as the answer and the Castel word.

The Fortress Part 1
The first thing that you need to notice is the acrostic. This was the first and most important hint. The first letter of each line in the instructions reads "Start with Saint Luke." There is simply not enough information to solve any of the other evangelists.
Bastion of Saint Luke:
This is where I screwed up. I made the Bastion of St. Luke too hard, or at least too ambiguous. I eventually gave the entire solution to this puzzle in the hints. In each line one word is incorrect. The correct words should be SEE-SIR-SHIFT-MARKS-EVEN-CALL-HUMS-FOUR-WARD-TOO-LETTERS-HAN-SURFACE-PLANT or Caesar Shift Mark's Even Columns Forward Two Letters. Answer: Face-Plant. The answer to this question is face plant and you need to adjust the even columns of Saint Mark's drop quote forward 2 letters. So A turns to C and G turns to I.
Bastion of Saint Mark:
After shifting the even columns forward two letters, then the drop code is solvable and isn't even all that hard. It reads. "Answer is role for which Bert Lahr was most famous. Decode Saint Matthew by Discarding Adjecent Identical Pairs Then Taking Differences. Repeat three times." The solution to this line is the role for which Bert Lahr is best known, which is the Cowardly Lion (from the Wizard of Oz).
Bastion of Saint Matthew:
Bastion of Saint Matthew is actually pretty straightforward to solve given the instructions from Saint Mark. It reads "JOHNIMGUROSCARQUEBECROMEOKILOZEROHOTELBIGALPHA" Which tells you to visit Imgur code oqrk0hA
That will give you the diagram that you need to solve the Bastion of Saint John. You are told that the answer is where you get sent. There are seven possible answers to this, of which the easiest answer is "IMGUR"
Bastion of Saint John:0
The vertical columns are OBIN, RIDE, BROW, RIOLE, UTHER, SPANS, CTRICH, BEATLE, ADMITS, IWI, VOX, OPT, SPREY, ALYNN, MERCI, AVEN, APSE, CAPO, ESTREL, SPIKED, SYNODS, GRET, CARE, SLUR, AGLE, RECUTS, ASHARP, ELICAN. Some of th'e columns have Letters, but the columns without letters are OBIN, RIOLE, CTRICH, IWI, SPREY, AVEN, ESTREL, GRET, AGLE, ELICAN. In keeping with Saint John, these are all birds minus their first letters. These are ROOKORKEEP. A word meaning "Rook or Keep" is "Castle" which is the answer to Saint John. This is the last puzzle and gives you the Castel word RARE.

The Fortress Part 2 (The Angel Courtyard)
The trick to this is that there is a clear hierarchy of angels. The most influential Christian angelic hierarchy was that put forward by Pseudo-Dionysius the Areopagite in the 4th or 5th century in his book De Coelesti Hierarchia (On the Celestial Hierarchy). During the Middle Ages, many schemes were proposed, some drawing on and expanding on Pseudo-Dionysius, others suggesting completely different classifications. According to medieval Christian theologians, the angels are organized into several orders, or "Angelic Choirs".Thomas Aquinas (Summa Theologica, I.108) follows the Hierarchia (6.7) in dividing the angels into three hierarchies each of which contains three orders, based on their proximity to God, corresponding to the nine orders of angels recognized by Pope St Gregory I.
Seraphim, Cherubim, and Thrones;
Dominations, Virtues, and Powers;
Principalities, Archangels, and Angels.
Simply order the angels into this order (there is one of each) and read down the diagonal (hinted at by the observation that you "make your way diagonally up to the Angel Terrace.") and it reads HIERARCHY, which is the answer. The Castel word is INDIA

Mastery of the Castel (the metapuzzle)
You have Pictures of 4 things to identify. These are a REIN, a DIAPER, a TURBAN and a CAMERA
The Castel words are ANGLO BECAME RARE INDIA PERTURB
The four pictures in the metapuzzle are almost the same words as in the Castel words, excepting as I noted that "my spacing may be a little bit off"
'ANGLO BECAME RARE INDIA PERTURB ANGLO BECAME RARE INDIA PERTURB' and
'AN GLOBE CAMERA REIN DIAPER TURBAN GLOBE CAMERA REIN DIAPER TURB'
You are given 4 of the five words that correspond to the castel words. The missing word is GLOBE, which is the answer to the Mastery puzzle. Sens actaully managed to solve this with only three of the Castel words, which I found very impressive.