Hey I booked BWI to Amsterdam for 473 all included and at that time I think Rome was at most 100 dollars more.  Then 2 days later it was more than 1000.  I think there are deals here and there that significantly decrease the price.  I would just check itasoftware.com everyday and try to find a deal that works.  Also, change your dates by a day or two that might help

That’s a long trip for just 2 full days on the ground. According to ITASoftware.com, the price drops from $1229 departing the 30th, to $812 departing the 1st. Sept. 1 is the start of “shoulder season” pricing for many airlines. Unfortunately, I don’t think that will work for you if the wedding is on that Saturday.

Consider instead going to another city, then adding a cheap flight hop to Rome. For example, I expanded your search to not only include WAS (National, Dulles, BWI), but also RIC and PHL, to LON, FRA, PAR, MUC, AMS, and ITA turned up $686 PHL to London (Gatwick) on the 31st (arriving the 1st). From Gatwick, you can add a hop to Rome for $204 on British Airways. I did not check flight times.

If these don’t work for you, then try consolidators listed in our new user thread—not only to ROM, but also check them for WAS to LON, AMS, FRA, PAR, MUC, VCE, DUB, and MIL to see if something cheaper turns up. For example, I see DUB in the low $600s; Ryanair and Aer Lingus serve Rome from there. I have not checked flight times. Unless you have an extra day in your schedule, you might just stick with whatever consolidator does better than $1229. Have you also tried your dates at BookingBuddy?