Table:
0
A
B
C
D
E
1
Summoned
Elected
Assembled
1st member
2nd member
2
30 September 1295+
1295
27 November 1295
John Cullebere
Simon de Holand
3
26 August 1296
1296
3 November 1296
unknown
unknown
4
6 October 1297
1297
15 September 1297
unknown
unknown
5
15 March 1298
March 1298
30 March 1298
unknown
unknown
6
10 April 1298
1298
25 May 1298
Thomas Halyday
Robert de Sywell
7
29 December 1299
1299/00
6 March 1300
John Wymond
William Benne
8
26 September 1300
1300/01
20 January 1301
John Wymond
William Benne
9
14 July 1302
1302
14 October 1302
Simon le Tanner
Robert de Sywell
10
12 November 1304
1304/05
28 February 1305
John Halyday
William Costyn
11
5 April 1306
1306
30 May 1306
Simon de Wilshamstead
Geoffrey le Blund
12
3 November 1306
1306/07
20 January 1307
William Costyn
John le Marescal

Questions and formulas:
Question: What is 2nd Member, when Assembled is "30 March 1298"?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,C1="30 march 1298"),5))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E12,C2:C12="30 march 1298"),5))
Level: medium
Question: What is Assembled, when 2nd Member is "Unknown"?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,E1="unknown"),3))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E12,E2:E12="unknown"),3))
Level: medium
Question: What is 1st Member, when Summoned is "14 July 1302"?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,A1="14 july 1302"),4))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E12,A2:A12="14 july 1302"),4))
Level: medium
Question: What is Assembled, when Summoned is "6 October 1297"?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,A1="6 october 1297"),3))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E12,A2:A12="6 october 1297"),3))
Level: medium
Question: What is 1st Member, when 2nd Member is "William Benne", and when Elected is "1300/01"?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,(E1="william benne")*(B1="1300/01")),4))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E12,(E2:E12="william benne")*(B2:B12="1300/01")),4))
Level: medium
Question: What is Summoned, when Elected is "March 1298"?
Formula: UNIQUE(CHOOSECOLS(FILTER(A1:E1,B1="march 1298"),1))
Formula2: UNIQUE(CHOOSECOLS(FILTER(A2:E12,B2:B12="march 1298"),1))
Level: medium