What are these books called??

reallyfoxnews:

Dear Tumblr, maybe you can help me. I’m on this kick where I keep remembering details from books I read as a child and then I Google search key words and find the titles of them and feel happy and nostalgic. I’ve found some pretty obscure books this way too. However, there are these two books that for the life of me I can’t find and no one seems to know what I’m talking about. I’ve been driving myself crazy for 2 weeks trying to find them. Help?

Book 1- There is a girl who is rich and lives with her parents. Her best friend is poor, and for her best friends birthday she receives a beautiful red diary. The rich girl is jealous and tells everyone at the party that her best friend wants to be a writer, which is her most personal secret. Somehow (maybe with a locket?) she gets transported back in time to this house where a family lives (maybe royal? Definitely rich) and I remember that there is a kitchen with the cooks and a drawing room and the guy who lives there falls in love with her and paints her portrait. When she is back at home she goes to the house, which is a museum, and finds the painting of her on the wall. 

Book 2- There are 4 or 5 princesses and each of them has a crown with a different jewel and for some reason they all need to get together and put the jewels together to save something (very captain America).

There is also a book and the only details I can remember are that it is about a girl at boarding school (maybe in Germany?) and they have to put gas masks on because they get bombed.

HELP MEEEEEEEE. <3 RFN

Is Book 2 the Jewel Kingdom series?  I read those forever ago as a kid.